These are some of our favorite sites...

TF sites...
Transformer World 2005 A coolass site with CR Episodes, a message board and lots more. Also hosts a few sites including The ToyArk (Lots toy pics) and Unicrons Realm (G1 stuff).
The Alt Mode by Trainimus Prime Changes toys around into alternative modes, very cool.
Cybertron City This site has G1 Episodes for download.
Transformer Matrix Go here for all the latest news, reviews and special articles.

Other Sites...

Gamefaqs All you need for videogames..
E-Lingo Translates websites into english
The Home for Unwanted Fanfics As the name says, also has lots of other stuff.