Usenet archives are often presented with a WWW interface. For that reason, I have combined the two categories here. Some are huge collections of the text posts and discussion groups going back for years, but excluding the binary posts. Others are comparable to the good pay servers in terms of the posts they carry and their retention time.

Google (formerly Deja News) has a advanced groups search
Yahoo has a usenet search

Open Directory - Computers: Usenet: Web Based
NewsOne.Net - Free Usenet Newsgroup News

AltaVista search for web-based usenet servers
NewsGuy allows WWW search of their pay server
News2Web gateway

Commercial WWW gateways to Usenet

1usenet dotcom
PictureView
NewsDump
BarDitch
Easynews
Usenet-Access.com