If you’re a big user of Gmail, Calendar, or any of Google’s other account-based services and have spread your data across multiple accounts, Google has a new feature that you’re going to love: Multiple Sign-In. Yes, you’ll finally be able to quickly swap between multiple Google accounts without having to go through the tedious process of logging out and logging back in every time. Granted, the process generally takes less than a minute, but for those of who have been doing it a dozen times a day, this is a very welcome change.

The feature, which was first noticed by Google Operating System, will only work for some Google Apps: Gmail, Calendar, Reader, Sites, Voice, App Engine, and Google Code. It is reportedly rolling out to users this week, and can be enabled through this page (I don’t see it yet). It’s also a bit confusing — you’ll probably want to read through the help section before you activate the feature (note that you can’t use offline access with Multiple Sign-In activated).