>Is there a log somewhere that exists when the application recycles? Or, should we handle that manually by adding a record in a Recycling table so we know when it happened?

Looks like you can configure IIS to do it (haven't tried it myself):
http://www.microsoft.com/technet/prodtechnol/WindowsServer2003/Library/IIS/87892589-4eda-4003-b4ac-3879eac4bf48.mspx?mfr=true

Failing that here's an example of getting the information in the Application end event:
http://weblogs.asp.net/scottgu/archive/2005/12/14/433194.aspx

HTH,
Viv