I'm a pretty big fan of cyberpunk.... Guilty pleasure, I guess, but at least I take none of it seriously like some out there...
Anyways;
For books, read William Gibson's Neuromancer trilogy - if you haven't already. There are others, but I haven't found them anywhere near as good, cyberpunk novels don't have a history of being much more than middlingsci-fi books, only Gibson stands out...
For games - play
Introversion's Uplink
The definitive cyberpunk games are System Shock 1&2 - The first can be downloaded, get the 2nd from eBay. Never recieved the interest they deserved, but now recognised to be major influences to Deus Ex, as well as great game sin themselves...
Deus Ex (If you haven't played it that's one of the biggest milestones in recent gaming history you'd have missed, despite being one of the finest cyberpunk games)
The game of Blade Runner, the postmodern cyberpunk film, is one of the finest point-and-clicks ever. Again - eBay (you'd be lucky to get a download of it)
The glorious Bullfrog, in their heyday, produced the cyberpunk themed Syndicate (google & download - the first's better than the second)
The Metal Gear games could be considered cyberpunk-ish
I have no Mouth and I must Scream (Underdogs / Google - can be downloaded - but not all that good IMO)
Dystopia - a mod for Half-Life 2 if you have it...
Beneath a Steel Sky (SMUMM-based point and click - Google & Download)
Google also for:
DreamWeb
Quarantine
BioForge
Omikron (Played the demo, looking to get myself a copy - David Bowie is in it!)
There are more, but those are generally the best...
There are some Cyberpunk RPGs and MUDs out there - but generally not so good (bear in mind Cyberpunk's peak was in the 80s...)