Gin Rummy

Eliters
Professional multiplayer gaming league. Daily tournaments, rules, application, calendar, prizes, and links.
http://www.eliters.com/games/league/default.asp?lid=giny

Flipside Gin
Ladder games, tournaments and message forums. This league is a member of Case's Ladder and plays on Flipside.
http://www.igl.net/fsgin/

Gin Rummy
Play Gin Rummy against a computer opponent with this Java applet.
http://www.geocities.com/SiliconValley/Server/6272/

Sancho's Gin Rummy
Play against a human or a robot. No JAVA required. WebTV compatible.
http://www.sancho.com/gin

World Play Gin
Ladder games, tournaments, tips and news. Free registration.
http://www.geocities.com/ea_gin/index.html