Gmail now offline

Here is the blurb by Google

Offline
by the Offline team

Make Gmail go where the Internet doesn't. Access your inbox through your browser and use Gmail's familiar features when you're offline. To get started, enable this lab and then click on the "Offline" link in the upper-right of your inbox.

Looks like a handy feature for those on the move. I've used Thunderbird in the past, but it looks like this might be my new ticket!