Previously only your regular GMail accounts had all the different Apps and Services provided by Google, but now even Google Apps has all these Apps and Services. I currently have ZDistrict running on Google Apps as well as several other domains. From your domain Management you can enable your Google Apps account to be migrated to the new Apps and Services which gives you access to Google Docs and all other documents. But the one drawback I wasn’t aware of at the time is that then I can’t sign into my Gmail account and my ZDistrict account at the same time. To do that I had to Enable Mulitple Account Signin from my main Google Accounts Page. Once that is done you can switch between accounts from a dropdown menu which is very cool, and I’m enjoying it, I sign into one and then use the drop down to switch between them.

Before you can turn it on, Google wants you to be aware of a few drawbacks, most notably that not all products support multiple sign-in and offline mode for Gmail and Google Calendar won’t work. I’m assuming that these will be worked out at a later stage but their was no mention of that from Google. But if you want to turn off Multiple Sign In and maintain the offline mode, you can still sign into your account with a little trick but using one Chrome Incognito Window to access that other account.

Link: GmailBlog