The Russian liberation movement/The Russian liberation army (Русское Освободительное Движение/Русская Освободительная Армия) was a group of Soviet soldiers who fought on the side of Nazi Germany during World War II.
This is fairly well-documented. The interpretation, however, is not. The following is an entry I wrote for Citizendium - which was, of course, immediately criticised as an interpretation and debate material rather than an encyclopedia entry - and of course there was a request for documentation, leading into yet another discussion about original research - and I could hardly to my Danish BA thesis for documentation.
Anyway you slice it, there is certainly a place for it here.

Declared foundation of the Russian liberation movement:
Proponent angle

A large group of Soviet soldiers wanted to fight for the liberation of Russia or the nations of the Soviet Union from the existing system lead by Iosif Stalin.
An opportunity to achieve this goal was presented with the German invasion. In June 1942, leaflets encouraging Soviet soldiers to lay down their arms and welcome Adolf Hitler as the liberator were dropped at the front and in the areas being occupied. As a counter-move, the Soviet leadership attempted to paint a picture of the German as an evil enemy – the Germans, who were allies a short time ago. As Soviet citizens were accustomed to reading between the lines in the official statements, this campaign made little impression on the population. Part of the Soviet soldiers and civilians had had contact with Germans in the 1st World War and could not match their personal impression with the one offered in official publications.
Also, this alliance gone sour produced another alliance with the former (and later) arch enemies Great Britain and USA. This strengthened the impression that the priorities of the Soviet leadership were not in reality what they were officially.
And so, there was an interest in an alliance with the German state. This because it was impossible to imagine that it could be the intention of German leadership to conquer and continually occupy all of the Soviet Union, due to its massive size – not to mention the experience with the Russian geography done by Napoleon. Ergo, it would be in the interest of Nazi Germany to cooperate with a group interested in creating an alliance, in which the Soviet Union – or Russia, depending on which interest group was consulted – would exist as a democratic republic – or, as some suggested, a monarchy again – which would be a supportive military and trade ally of Germany.
Germany was seen as a nation with positive associations, because it was part of a European traditionally shared cultural community. It also had a certain effect that it was a practising Christian society, as opposed to the Soviet Union, in which the state had made a substantial and rather heavy-handed effort to eliminate religious practice.
The figurehead of the movement was Lieutenant General Andrey Andreyevich Vlasov, a decorated war hero, who had made his way up through the ranks of the Red Army, based on merit. In the autobiography of one of the leaders of the Southern Front, responsible for the defence of Kiev – and later General Secretary Nikika S. Khrushchev, Vlasov is mentioned as an able commander.
After the defeat of his 2nd Shock Army in the summer of 1942, Vlasov is captured by German forces. He offers to fight in an established Russian liberation army.
While working on this, he stresses some good things with the Soviet system as opposed to Imperial Russia, but he also stresses that which is unacceptable in the new system – that the system is not, what it is pretending to be. The German army responded positively to the idea, but postponed taking full advantage of it due to the scepticism of the political leadership, based on ideological issues. Vlasov was allowed to travel to POW camps and occupied areas, where he presented his cause – which was popular, and the soldiers already active in the Wehrmacht, albeit not as part of a common coordinated force, started wearing the ROA insignia, as they saw themselves as part of a shared cause – a liberation army.

The Soviet official position:
Critical angle

A minor group of Soviet citizens cooperated with the German occupation force. The collaborators were either former prisoners of war or soldiers and civilians, who changed sides during the war.
Having surrendered to the invaders, the prisoners of war were already counted as traitors by Soviet definition, as these were considered people, who were not willing to make an effort and sacrifice to defend their country – who had let themselves get surrounded on the battlefield and taken the easy way out by surrendering instead of fighting to the end. Volunteering for the liberation movement after capture demonstrates their weakness, either by making the choice based on threats of physical abuse, or allowing themselves to be bribed with pay, food and relative freedom.
The soldiers and civilians, who changed sides, were perceived as cowards and opportunists in the same fashion, as people willing to sacrifice the future of their homeland to be on the (apparently) winning side, where it was possible to gain something for oneself. It was seen as typical for the kind of people who are weak and deceitful by nature – or as a variation of this, people who had lost land, fortune and privileges with the people’s revolution, well-off families and large-scale farmers (kulaki), who had no interest in the preservation of the Soviet Union. Vlasov had allowed the defeat of the 2nd Shock Army and surrendered to the German army in order to live comfortably and benefit. He, too, was a chameleon, who made his alliances, where he found a winning side. Upon capture, he let the Wehrmacht use him as a propaganda marionet, partly to weaken the moral of the soldiers of the Red Army, partly to keep the prisoners of war passive and partly to recruit troops, that could be used for various purposes of use to the Wehrmacht. This treason was compounded by the establishment of the Committee for the Liberation of the Peoples of Russia (KONR), where he not only let his German masters lead him, but actively took control in the campaign against his homeland.
The assumptions about Vlasov are confirmed by the circumstances around his capture by Soviet soldiers; he was captured on the way to the American sector, where he was found to be in possession of a large amount of money. This is interpreted as meaning that he had gained what he could and was searching for a new winning master – yet another capitalist state, which the USSR had allied with temporarily, but which should be treated with caution. During the final trial in 1946, he admitted to having lost heart, that he was offended by his country, and admitted to his treason. So, when he and his inner circle were hanged, they got the punishment which was to be expected and deserved for traitors of such a caliber.

References

There is a lot of material on the topic - as you may suspect from the view expressed above, it is a challenge to find balanced material on this.
I have found the following two to be the most comprehensive:

• Catherine Andreyev: Vlasov and the Russian Liberation Movement Soviet Reality and Emigré Theories. Cambridge Russian, Soviet and Post-Soviet Studies, 1990. (Openlibrary entry)
• Joachim Hoffmann: Wlassow gegen Stalin. Die Tragödie der Russischen Befreiungsarmee 1944/45. Herbig, 2003. (OpenLibrary entry)

There are also interesting memoirs:

• Wilfried Strik-Strikfeldt: Against Stalin and Hitler. Memoir of the Russian Liberation Movement 1941-5. Translation by David Footman. London: Macmillan, 1970. (OpenLibrary entry).
  Translated from: Wilfried Strik-Strikfeldt: Gegen Stalin und Hitler. General Wlassow und die russische Freiheitsbewegung. 2. Aufl. 1970. (OpenLibrary entry)
  On Strik-Strikfeldt’s experiences as an interpreter for the German army, ending up as a contact officer between the German leadership and Vlasov and his group.
• Артемьев В.П.: Первая дивизия РОА. London: Издательство Союза Борьбы за Освобождение Народов России (СБОНР), 1974.
  About the activity of the 1st KONR division, which Artem’iev was in.
• Казанцев А. С.: Третья Сила. История одной попытки. Изд. Посев. Frankfurt-am-Main, 1974.
  Mr. Kazantsev was a journalist and writer who was with the press department of the Russian liberation movement.

Also, a couple of additional articles of interest:

• Катусев А. Ф., Оппоков В. Г.: Иуды (Власовцы на службе у фашизма). Военно-Исторический Журнал 6/1990, p. 68-81. Москва: Изд-во “Красная Звезда”, 1990.
  About the trial and motives of the KONR leadership.
• Кринько Е. Ф.: Коллаборационизм в СССР в годы Великой Отечественной Войны и его изучение в российской историографии. Вопросы Истории 11/2004, Moscow. P. 153-164