Apple has just released a new version of their ITunes software (7.6) that includes a new version of their calendar synch add-in. The new version seems to fix all the previous problems with Outlook crashing or hanging after synching calendars, causing problems for other add-ins, and in crashing Outlook when connected or disconnected using the COM Add-Ins dialog.

If you sync your Outlook calendar with iTunes, you should install this update.

iTunes
http://www.apple.com/itunes/download/

An Outlook Add-in Bug
http://www.slipstick.com/ emo/2007/up071129.htm#2