Validatrix makes good use out of regular expressions. There are a number of resources online to help you with generating them.
For a good overview and tutorial
http://www.regular-expressions.info/
For applications that help you design regular expressions:
http://www.ultrapico.com/expresso.htm
http://www.regexbuddy.com/create.html
If you would like us to develop them for you then we can do that too (at our usual rate)