Note: This no longer works for me, but google has updated their page so it's no longer necessary. Check out my quick article on Google Gmail Multiple Account Logins.

You can create a bookmark that automatically logs you into your Google Email (GMail) account. This gives you a quick link to your email and also gives you an easy way to login to multiple accounts easily.

Note: Both of these methods give anyone with access to your computer access to your email AND your Google password.

Simply create a new bookmark (or favorite) containing the following URL:

https://www.google.com/accounts/ServiceLoginAuth?continue=http://mail.google.com/gmail&service=mail&Email=USER&Passwd=PASS&null=Sign+in

Replace USER with your Google username and PASS with the associated password.

If you use multiple GMail accounts, you'll need to log out of one and into the other, which takes an extra layer of foo.

Create a new bookmark (or favorite) containing the following URL:

https://www.google.com/accounts/Logout?continue=https%3a%2f%2fwww.google.com%2faccounts%2fServiceLoginAuth%3fcontinue%3dhttp%3a%2f%2fmail.google.com%2fgmail%26service%3dmail%26Email%3dUSER%26Passwd%3dPASS%26null%3dSign%2bin

Replace USER with your Google username and PASS with the associated password.

I gathered the basic URL information from an Article by Marco Kuiper. I expanded on that by using a few bits from the Jaret's source code for the Google Account Multi-Login plugin. Thanks guys!