IMF Updates explained

Alexander at EHLO has posted a very good description of how to enable automatic updates of IMF v2 and the functionality of IMF updates

IMF updates are twice per month
IMF updates are only supported on Exchange 2003 Servers with SP2 where IMF is enabled
IMF updates are supported on all Exchange server languages
IMF updates are available from Microsoft Update via both manual and AU
IMF updates supports uninstall through Add/Remove Programs and manual rollback

Find it here