Top 10 Guitar Tab Sites on the Web
Guitar Tab Universe
This site has a big archive of a lot of the tabs found on OLGA, and elsewhere on the web, but does a good job of updating regularly.
MXtabs.net Guitar and Bass Tabs
This site maintains a regular update schedule, so you'll find a lot of new alt rock tabs here (Blink 182, Marilyn Manson, Green Day, Creed). Server can be slow at times.
OLGA (Online Guitar Archive) Guitar and Bass Tabs
Although it definitely remains one of the best archives on the web for older songs, frequent server issues and a somewhat disorganized setup make OLGA a little cumbersome. Many sites update more frequently, so if the tab you're looking for is from a newer song, try other sites first.
Rockin' With the Cross
If you're looking for Christian rock guitar tabs, you'll find an archive of almost 5000 songs here. Site also includes bass tabs, and even horn tabs.
Taborama Guitar and Bass Tabs
This site does a nice job of updating regularly. Use the archive links on the left side of the page to access all guitar and bass tablature. Taborama also includes drum tabs, keyboard tabs, and lyrics.