Here is the latest in my link-listing series. Also check out my ASP.NET Tips, Tricks and Tutorials page for links to popular articles I've done myself in the past.
Behavior Changes for ASP.NET applications running in Integrated Mode on IIS 7.0: Mike Volodarsky from the IIS team has a great blog post that details behavior changes for ASP.NET applications when they run in "integrated mode" on IIS 7. "Integrated mode" enables ASP.NET developers to take advantage of much tighter integration with IIS - and enables a host of additional scenarios (richer URL rewriting, integrated authentication/authorization, etc). If one of the behavior changes listed in Mike's document impacts your application, you can optionally change the application to run in "Classic Mode" - which maintains the same ASP.NET behavior as with IIS6.
Hope this helps,