Regular Expressions

Resources:

http://www.regexp.com/
http://www.regular-expression.info/

4GuysFromRolla - Regular Expressions
http://www.4guysfromrolla.com/webtech/RegularExpressions.shtml

Greg Reinacker's Weblog
Nested Constructs in Regular Expressions (using .NET)
http://www.rassoc.com/gregr/weblog/archive.aspx?post=590

Using a Regular Expression to Match HTML
http://haacked.com/archive/2004/10/25/1471.aspx

Tools:

Dela's Ramblings
Regular Expression Library Builder
http://briandela.com/blog/archive/2005/06/03/284.aspx