Regular Expressions library

Regular Expressions (REGEXs) are not something I would expect to be blogging about about, but I have had more exposure to them recently since my company's software (Directory Update and Directory Manager) use Regular Expressions for data validation. So I am frequently either asking one of the programmers to create me a REGEX that validates some string or number. One of my developers politely showed me the Regular Expressions library site. I must say this is a nice site and VERY helpful. (By the way, you can use REGEXs for string/number searching with Exchange 2007 Transport Rules!)