Team Fortress 2

Control Point
Podcast, news, forum, and server.
http://www.deadworkers.com/tf2/

The Fortress
Comedy series done within TF2. Downloads and forums.
http://team-brh.com/thefortress/

Fortress 2 Allegiance
Site created long before the game was released with information and screenshots. Gives a look back in time to an earlier stage in the development of TF2.
http://www.angelfire.com/hi2/tf2/

The Orange Box - Team Fortress 2
Official site containing information, screenshots, and trailers.
http://www.whatistheorangebox.com/tf2.html

Planet Team Fortress 2
Site created before the game was released. Includes old screenshots and information that gives a look back in time to an earlier stage in the development of TF2.
http://www.planetfortress.com/tf2/

Team Fortress 2 Fort
News, forums, images, and contests. Also has a competitive and a community clan with own servers, ventrilo, and chat.
http://www.teamfortress2fort.com/

Team Fortress 2 Stats
Official steam statistics on the classes, weapons, maps, and achievements.
http://www.steampowered.com/status/tf2/tf2_stats.php

Team Fortress TV
Video podcast that covered the first TF2 tournament arranged by Cevo.
http://www.teamfortress.tv/

TF2 Insider
Weblog covering news, tutorials, scripts, and exploits.
http://www.tf2insider.com/

TF2 Strategy
Guides for all classes and official maps, miscellaneous guides, and forums.
http://tf2strategy.com/

TF2 Wiki
Collaborative edited site with information on classes, maps, strategies, and customization.
http://tf2wiki.net/wiki/Main_Page

ubercharged.net
Weblog with focus on tutorials and humor.
http://www.ubercharged.net/

Wikipedia - Team Fortress 2
Article that covers basic information, gameplay, and the development in a historical perspective.
http://en.wikipedia.org/wiki/Team_Fortress_2