1/ The Sector 7 site has, for some time, featured this zip file of an unofficial TF (movie?) theme-tune. The cheese really goes all the way to "mature stilton" just when someone on helium starts saying some TF names.
Check it out here:
http://www.sectorseven.org/OHD2/deceptibot/theme.zip
2/ Black Lab have made a cover of Stan Bush's "Transformers: The Movie" (animated) theme for their forthcoming album.
Check out their official page here:
http://blacklabworld.com/blw/pages/transformers.html
You can download the full (if badly edited) High-Def "music video" if you scroll down their homepage (rumour has it the track is available at rapidshares.com but posting direct links to such things goes against both TFans and rapidshares, so DONT please).
3/ Of course, as we all know, "Mutemath" also released their own version (which now seems miles better, when compared to the other two...maybe):
http://www.last.fm/music/Mute+Math/_/Transformers+Theme
Again, rapidshares might also host this, but remember: piracy is illegal, so go buy the ahem, "great" and "definitely worth it" Transformers: Soundtrack, which isnt just a vague collection of hastily put together and mainly unrelated to the movie tracks.
Oh no siree...