VernorVinge's 1980 story TrueNames featured a computer network that people interacted with in an immersive way, and WilliamGibson's 1983 Neuromancer popularized the idea rapidly. Today, VirtualReality exists in some degree, and it's widespread use is generally assumed in any ScienceFiction story set in our near future.
A good use of VR (and the closely related ArtificialReality) is EricNylund's SignalToNoise which I recently read and enjoyed thoroughly. -- SunirShah
"A young boy puts a feather in his mouth..."
Also have a read of Vurt ISBN:0312141440 by JeffNoon. A vurtual [sic] world played as a game but which starts to leak into the real world. Psychedelic CyberPunk. -- PaulMillar
this is a great book! I loved it! -- BayleShanks