The Solomon R. Guggenheim museum in New York City has, on display through the web, several pieces of "early Internet art". The museum also has this fascinating discussion of the valuation of art produced on or specifically for the web:

It is possible, however, to hypothesize a Web site's putative value independent of its price tag in an exchange economy. That value would be the sum total of money a museum would be willing to spend over time reprogramming the site to ward off obsolescence.

Those poor kids at deviantART have been slaving away for a pittance...