Many applications today have several common security problems. SQL Injection, poor authentication and authorization, and Cross Site Scripting (XSS) vulnerabilities. The faster and more conssitently we can address these problems the better the security of our application is.
Microsoft has released version 1.5 of the Anti-XSS library. You can download it for free from: http://msdn2.microsoft.com/en-us/security/aa973814.aspx
It's designed to help you protect your web sites from XSS vulnerabilities in a clean, and conssitent manner. Check it out!