Debugging and Error handling in SharePoint (or other complex ASP.NET applications)

http://sharepointexception.wordpress.com/

http://blogs.msdn.com/b/jannemattila/archive/2008/02/23/crm-4-0-sharepoint-and-asp-net-trace.aspx

http://blog.thekid.me.uk/archive/2007/07/25/debugging-tips-for-sharepoint-and-wss-exceptions.aspx

http://www.codeproject.com/KB/sharepoint/Handling_Error_Centrally.aspx