This is a simple application to test QRegExps. It shows you the captured strings and their respective substrings. It is based on the popular Qt framework and runs on Windows, Linux and MacOSX.
The latest release of QRegExp-Editor is version 0.2.1 (released on 2012-03-21) and can be downloaded here. You'll find binaries for windows and macosx alongside the sources that are platform-independent.