JScript may be a bit easier here than VBScript, unless you're already more familiar with VBScript. JScript has built-in support for regular expressions, which makes life a bit easier. It's also much more common in other places like on the web. (Javascript isn't quite the same as JScript, but the basics are almost identical.)
This is probably a good place to start, since it already deals with applying regex to files in rename scripts:
That has examples in both JScript and VBScript, so you can pick whichever you prefer.
Shout if you get stuck or find it too complicated. I haven't had much time spare today but if I do I might be able to help out in more detail if it's needed.