So, Google/Chromium have released sample extensions for Chrome and Chromium (link) dev/beta builds.

One such extension is Google Mail Checker (link), which uses very nice graphics and a simple polling script to check for new Gmail messages.  Now, the problem is that the extension only works for Gmail.com users and not Google Apps users.

This is easily fixed, though, through editing of the background.html file (which houses the extension javascript):

Locate your Extensions folder.

Windows 7:

C:\Users\%USER%\AppData\Local\Google\Chrome\User Data\Default\Extensions\

Windows XP:

C:\Documents and Settings\%USER%\Local Settings\Application Data\Google\Chrome\User Data\Default\Extensions\

Locate the Google Mail Checker extension through digging in each folder (look at Date Modified), and then locate the background.html file in the \1.0\ folder.

Open the background.html file in an HTML editor (WordPad, Notepad, etc.).

You’ll see two variables linking to mail.google.com, which you have to edit to point to your Google Apps account:

var gmail = “http://mail.google.com/”;

var gmailAtomRef = “http://mail.google.com/mail/feed/atom”;

To edit them, just insert your Google Apps URL (replacing DOMAIN.COM), like so:

var gmail = “http://mail.google.com/a/DOMAIN.COM”;

var gmailAtomRef = “http://mail.google.com/a/DOMAIN.COM/feed/atom”;

Save your background.html (you can make a backup of the original if you want), restart Chrome, load your Google Apps mailbox and you should notice the icon red instead of with a question mark.