Here's a blog post showing how to extend an existing website to use IronPython. The configuration is pretty much easy.
The post is meant for the "IronPython for ASP.NET" CTP, but it also is valid for the version of "IronPython for ASP.NET" shipping with ASP.NET Futures May CTP.
Also, The post is in Chinese! Don't worry, the screen shots and code samples are all you need to go.
Read the article.
Update:
Everybody is linking to it now, but just in case! If you haven't already, check out this great online IronPython Cookbook.