I find that this does cleanup all the content that is no longer needed in WSUS, but i am getting an error reported in the log when the SQL maintenance script is run:

Timeout expired.  The timeout period elapsed prior to completion of the operation or the server is not responding.

Is there something i need to do / change to make this script finish?  What is not being missed because of this timeout?

Thanks.
Bill

I would recommend trying to run the cleanup from management studio or use sqlcmd as described here:
http://technet.microsoft.com/en-us/library/cc708594(WS.10).aspx

The timeout in studio manager or sqlcmd should allow for longer execution time.  Once you run it initially and get the database cleaned up the subsequent runs with this tool should work.