Regex Builder has moved to a new home, and I've released a new 2.05 version with a few fixes and new features. It now offers a VB or C# preview of the code to run the expression (automatically escaping string terminators in the target language) and offers the ability to unescape characters (helpful for going back from code to Regex Builder)

You can find it at http://www.codeplex.com/regexbuilder.