Portal

GameFAQs
Cheats, reviews, images, and a message board.
http://www.gamefaqs.com/computer/doswin/data/934386.html

GameSpot
Reviews, news, previews, images, videos, cheats, and a forum.
http://www.gamespot.com/pc/action/portal/

GameSpy
Review, previews, news, screenshots, and movies.
http://pc.gamespy.com/pc/portal/

IGN
Videos, screenshots, cheats, guide, reviews, previews, news, and a message board.
http://pc.ign.com/objects/842/842671.html

Wikipedia
Article describing gameplay, synopsis, development, and critical reception.
http://en.wikipedia.org/wiki/Portal_(video_game)