Mykonos own Kyle Adams just did a presentation at the Rochester Security Summit 2009 on using Regular Expression for securing and filtering user data.
The presentation covered the use of regular expressions in 3 common attack cases: XSS, SQL injection and insecure direct file reference. Kyle showed a few examples of the attacks, and how the use of RegEx can prevent them. You can check out and download the presentation here. Additional information about the summit can be found at the Security Summit’s website.