I have a copy of uplink, and it's fun, but... Well, it does't require a whole lot of thinking. It's really a very glorified script kiddy sim/spy game (which doesn't make it ant less fun, and it DOES have a plot, which sadly most online hacking games lack). Most people don't even know how to bypass a javascript applet.
http://www.try2hack.nl/ is a pretty good site for newbies, I just started and got to level 6, no sweat. Anyhow I find these sites a good (FREE) way to have fun. If anyone wants to brag about thier skills, I'd welcome sombody to compete with
