Cyberpunk is a subgenre within science fiction. Stories in this genre are about: computers, robots, hackers and the impact of an information society on individuals and often the alienation advanced technology poses to the individual. In some stories, like in William Gibson's Sprawl Trilogy, humanity has reached a technological singularity and thus, to true artificial intelligence.
The heroes in cyberpunk stories are usually hackers, but they are not heroes in the classical sense.
Examples of this genre are: Neuromancer, Count Zero, Mona Lisa Overdrive, Virtual Light, Idoru, Burning Chrome, among others, by William Gibson and Wyrm, by Mark Fabi.