http://www.regxlib.com/default.aspx
http://sourceforge.net/projects/regulator/
Http://www.sellsbrothers.com/tools/Have a lot of .NET tools
http://www.gotdotnet.com/community/Usersamples/details.aspx?sampleguid=c712f2df-b026-4d58-8961-4ee2729d7322
Regular expressions in ASP.NET