If you have any combination of multiple Google Apps and Gmail accounts, you're probably sick of signing out and signing in to different accounts to do different things.
Fortunately, Google allows "multiple account sign-in" that can alleviate the pain. Makes it sooo much easier to manage all that email.
The feature is not supported across all Google services (like Blogger, for example). Not working for you? Try these other solutions from TechRepublic.