My blog has now been changed to http://blogs.technet.com/mfugatt This site will continue to exist but all new postings will be made to my new blog.
Paul Flaherty has produced a BlogCast on troubleshooting IMF, well worth checking out: http://blog.flaphead.dns2go.com/archive/2005/06/17/2780.aspx
Evan Dodds has posted a really cool article about configuring IMF gateway settings on a per server basis: http://blogs.msdn.com/evand/archive/2004/09/05/225916.aspx
Well, I learnt something new today, someone posted a question in the microsoft.public.exchange.admin newsgroup about IMF not working once they had installed it, they had double-checked that they had enabled it on the SMTP Virtual Server (a common oversight...