Frank Welker, the man who voiced Megatron in the original animated series, as you know was not chosen for the 2007 movie adaptation of Megatron in favor of Hugo Weaving. His co-star Peter Cullen however was, thankfully, recruited for Optimus Prime.
Michael Bay has recently revealed that he wants Frank Welker to voice a villain in the sequel Transformers 2: Revenge of the Fallen.
Bay said that he will pursue Welker for the role of Soundwave.
Soundwave was a Decepticon who shape-shifted into a cassette player in the original cartoon. In Transformers: Revenge Of The Fallen he will become a satellite.
Bay also has admitted that Megatron will be back for the sequel, for those of you that did not know already.
The article can be found at: http://www.digitalspy.com/movies/a149293/welker-to-voice-transformers-2-villain.html?imdb
This second bit is about the other character. This was found on screenrant.com
it is more rumor than confirmed, but the reasoning is pretty solid.
John Turturro, who of course played agent Simmons of Sector 7 in the first film, has been found to be voicing a Transformer as well as reprising the Simmons role in the sequel.
A user on the official Michael Bay forums read something interesting from the French movie magazine Première Ciné Live and translated it for the forum. It revealed potential plot spoiler as well as who Turturro may be voicing, Jetfire.
Jetfire better known as Skyfire in the original Transformers cartoon is a flying Autobot. Jetfire in the film is disguised as a SR-71 Blackbird.
In the original cartoon Skyfire was a Decepticon who was a close friend of Starscream. He and Starscream came to Earth On a mission to explore prehistoric Earth, Skyfire was lost in a storm. Starscream searched, but there was no sign of his comrade, and assumed he was destroyed. He returned home.
Millions of years later, after the Autobots and Decepticons had begun their war on Earth, the Decepticons found Skyfire, encased in a block of Arctic ice, ala Captain America, and revived him. Skyfire joined them due to his friendship with Starscream, though he disliked their methods. When Skyfire's compassion led him to disobey Megatron, Starscream turned on his friend. Skyfire then left the Decepticons and joined the Autobots.
This is a paraphrased version of the quote from screenrant.com
Spoilers!
This is not in my own words, I’m just reposting it.
In Egypt- In front of Kheops Pyramid, stands an ancient palace built for King Faruk’s guests. At “Action”, Shia runs through the yard, stops at the doorstep and hits the door with his shoulder. Megan Fox, John Turturro and Ramon Rodriguez follow next and hurry inside the building.
Shia heads up, shout a few words at an imaginary Bumblebee, and gets in.
Three cars, the Camaro, the red TRAX and the green BEAT, start quickly and stop a bit further away to look out. The three vehicles are driven by black-suited (and thereby “invisible”) stuntmen behind the smoked glass.
At the end of the day, the crew moves to the third and smallest pyramid, Mykerinos.”
The article goes on to report that Michael Bay says “There is also an old Transformer, who loses screws and bolts at every move and it’s John Turturro voicing him.”
He also goes on to say that two Autobots Skids and Mudflap, are basically the comic relief of the movie. And Bumblebee has become a bit more serious in the second film as well.
Well that’s it. You can check out the rest of the article here at http://screenrant.com/john-turturro-plays-transformers-2-rob-6112/