Gmail Indexer allows you to search your Gmail directly from Google Desktop Search.

Regularly index your entire Gmail account contents into Google
Desktop Search. This is done using Gmail?s POP access feature.
See the following URL for information on how to enable POP access
on your Gmail account:
http://gmail.google.com/support/bin/answer.py?answer=13273&topic=194

To install, follow these instructions:
1. Verify that POP access is enabled on your Gmail account. If
you have used POP access with Gmail before, it's recommended
that you disable and enable it again so that you can receive
all of your old email using this plugin.
2. Run the "LarrysGmailIndexer.exe" file in the zip.
3. Agree to the registration with Google Desktop Search.
4. Log in using your Gmail email address and also your regular
Gmail password.
5. Indexing will happen immediately. You can watch the emails
being indexed by using the Index Status link in GDS and looking
at the "Emails" counter.

To uninstall, follow these instructions:

1. Go to your Start menu and select "Control Panel".
2. Select "Add/Remove Programs"
3. Find "Larry's Gmail Indexer" and click "Remove".
4. Thats it!