It seems that Michael Bay is listening to the fans. Director Michael Bay has posted on his message board forums the he is going after Frank Welker, the original voice of Megatron, for the voice of Soundwave in Transformers: Revenge of the Fallen.
The director responded to a fan thread, which cited an interview with Welker and pled for the director to use his voice, with a brief statement.
I think I'm going to pursue Frank on Soundwave.
We'll surely keep you posted on any and all news regarding Transformers: Revenge of the Fallen, as soon as we have more information.