Thomas Holloway and I developed a powertoy for building, validating, and parsing regular expressions. Thomas posted a wonderful article with more information here. This application is definitely a handy one. We have feedback from many University students and professors about the use of the software. Also, we have questions about how the Swing interface was implemented. Overall, a wonderful product that will hopefully be very handy to developers. Feel free to build from the subversion, but be warned, the project is not released yet.
We planned on having a release for the software last week. However, like most software, stuff happened. I will be posting the beta as soon as I get back to Utah (another week or two).