WSS v3, MOSS 2007 Forms Based Authentication importing users, forums and posts – part 2!
Impersonation and Event Handlers
http://www.sharepoint-tips.com/2007/03/event-handler-impersonation-continued.html
http://www.sharepoint-tips.com/2007/03/impersonation-in-event-handlers.html
Impersonation and SharePoint 5
Part1: http://dotnetjunkies.com/WebLog/victorv/archive/2005/04/20/69524.aspx
Part2: http://dotnetjunkies.com/WebLog/victorv/archive/2005/04/20/69519.aspx
Part3: http://dotnetjunkies.com/WebLog/victorv/archive/2005/04/20/69521.aspx
Part4: http://dotnetjunkies.com/WebLog/victorv/archive/2005/06/30/128887.aspx
Event Handlers, Impersonation and SharePoint 2007 (Patrick Tisen)
Run SharePoint Code With High privileges
http://coppercoins.spaces.live.com/blog/cns!E15FE96DB520E62C!140.entry
Security Validation and Making Posts to Update Data (Microsoft)
http://msdn2.microsoft.com/en-us/library/ms472879.aspx
Great Post on Sample Event Handler with Impersonation