Here are all the links to the *best* Transformer sites on the web. Other good sites can be found on the "Addedum References" page of this site. Enjoy:
Official Hasbro Transformers Web Site: Mainly deals with just Beast Wars and Beast Machines stuff.
The Transformers Archive: Lots of downloadable TF images/sounds/movies and more available here!
BigBot.com: The best site out there on the latest news concerning Transformers, as well as links to other superb TF sites.
Rockman's Robots In Disguise: A good place for info of TF merchandise, and plenty of great downloads. Run by TF episode dealer Rockman666!
Marvel Universe: Transformed: A TF fanfic group about a shared TF and Marvel Universe and it's characters. Great Stories!
Botcon: Annual Transformers Convention Official Site: Botcon is the annual American transformers convention, and this is it's official web site! Check here for the latest buzz on the where the next convention will be, who will be there, what will be available for purchase, and more!
Primus Comics: Another TF fanfic group that is a collection of different people's TF fanfiction. A very good TF group.
Radio Free Cybertron: A very good TF news site. Check it out.