Free

Active Exploits Diceless Roleplaying
Diceless roleplaying system with multiple setting books.
http://www.pigames.net/ae.php

Bedlam
A Megalomaniacal Storytelling Game.
http://www.realms.org.uk/bedlam/

Borderline Publications
Home of three system for different ages: Spy-Fi (60's), Pirates (1660's) and Chronos (Varies).
http://www.sreilly.pwp.blueyonder.co.uk/

Chris' Compendium of Free Role Playing Games
Links to various free systems available on the Internet.
http://www.homebrew.net/games/

Faunae
A free system about animals and their exploits in a world inspired by both fables and realistic nature.
http://koti.mbnet.fi/~atolonen/faunae/faunae.html

Harlekin-Maus
Monthly releases of small games.
http://www.harlekin-maus.com/index.html

Heavy Ordnance
Using the Reflex System players live out their childhood fantasies.
http://www.homebrew.net/games/heavy.html

Infinite Quest the Game
Free RPG, based on Heroquest. Free downloadable tiles, adventures, manuals and such. A must see for starting players and Gamesmasters.
http://www.infinitequest.net

Jons Page'O'Stuff
The site offers five free games. Three RPG's (one near-future cyberpunk type, one dark ages and one star trek type) and two quick-play board games.
http://www.urbanmyth.karoo.net/

Mind's Eye Publishing
Publisher of several free games and sponsor of the Free RPG Webring.
http://mindseye_x.tripod.com/

Soap
The game for those who can't get enough of weird soap opera drama and twisted plots.
http://www.nettrash.com/users/crayne/soap.html

Truerune's Suikoden RPG
A system based on the Suikoden Video Game Series published in Word .doc format.
http://www.angelfire.com/rpg2/suikodenrpg/Main.html

Yahoo! Groups: rpgwritersclub
The RPG Writers Club, a message board and chat room for amateur game designers.
http://games.groups.yahoo.com/group/rpgwritersclub/