CookiePie is a Firefox extension that enables you to maintain different cookies storage in different tabs and windows.

What good is that?

Here's one cool feature:

Switch CookiePie ON in two tabs, and you can log in to different GMail® accounts in each one.

Yes it works. ;-)

Download:

http://www.nektra.com/products/cookiepie-tab-firefox-extension


Instructions:

1) Right-click a tab and select "don't load cookies".

2) Sign into your first Gmail account.

3) Open another tab. Right-click tab and select "don't load cookies".

4) Sign into your second Gmail account.