Regular Expression Library
Historical article · Originally published May 6, 2003; technical details may be outdated.
This looks like a very good regular expression repository
Update:
Darren Neimke Says:
"Check out the new CheatSheet that Steve added last night --> get to it via the CheatSheet link on the side menu."
I agree. It's very nice. Still, I'd like to see there some stuff that was not copy-paste from MSDN.