Regular expressions are a powerful tool. I suggest the free Windows application, Expresso from http://www.ultrapico.com/. It allows you to test regular expressions.

I've used regular expressions at work and also for my personal applications. I have a write-up of a personal project and it has a brief mention of using regular expressions: http://www.codeproject.com/Articles/21847/NASA-Space-Shuttle-TV-Schedule-Transfer-to-Outlook