Regular Expressions in .Net
I think I am becoming a .Net Junkie. Either way here's a good reference for regular expressions in .Net:
http://aspnet.4guysfromrolla.com/articles/022603-1.aspx
Also a couple of good tools to help with regular expression development:
Regulator: http://regex.osherove.com/
Expresso: http://www.ultrapico.com/Expresso.htm