- Only 3 accounts can be logged in at a time. If you need to login to more than 3 Google Apps or Gmail accounts, you will need to open a second browser.
- Login with your preferred Blogger/YouTube account first. If your blogs and youtube accounts are all under an @gmail.com account, then login with that account first. If you login to Gmail with your @googleapps account, then login to your youtube account with your @gmail.com address, Gmail will logout your @googleapps account, and login with your @gmail.com account. (A real pain!)
- Don't forget to turn ON Google Help for your Google Apps domain!! Unbelievably, it is not available to your @googleapps accounts until you enable it in your Gmail domain administrator interface...
I'm sure there will be more :P I must say that the current state of the Google Apps Infrastructure migration is much better than when I first beta-tested it in Oct.(?) At that time, there was no multi-login capabilities yet, so I had to have two browsers open, (ala pre-Opera/Firefox tabs days :( ).