There has been a lot of voice-acting news recently!
Unlike a false news story that came up last year regarding War For Cybertron, Leonard Nimoy is indeed returning to the Transformers franchise. This is quite exciting as its another throwback to the original 1985 Animated Movie. This news comes from a post by Entertainment Weekly where Michael Bay discusses how Mr. Nimoy became involved and his relationship with him.
I for one, am happy to see him come back! Bring on Dark of the Moon!