4 links
Battlefield Nation
bfnation.net
Includes forums, guides for each game, and a downloads area with maps, modifications, patches and demos.
Battlefield Singleplayer
planetbattlefield.com
Offers AI articles, forum and downloads area with maps and modifications.
Eve of Destruction
planetbattlefield.com
A modification for Battlefield: Vietnam and Battlefield: 1942. Includes news, forums and downloads.
Planet Battlefield
planetbattlefield.gamespy.com
Features news, mods, interviews, tweaking and strategy tips, game information. Official GameSpy Planet site.