Coming to an Ubuntu box near you
Here is a screenshot of Ubuntu 8.04 “Hardy Heron” alpha 4, freshly booted up from the live CD. The first thing I did before anything else was load up the keyboard preferences:

Sure enough, there it is. So far, Colemak is only available for the US keyboard layout, but it’s a start.
To switch to Colemak:
- Go to System > Preferences > Keyboard
- Choose the “Layouts” tab
- Click “Add”
- Under “Layouts” choose “US” and under “Variants” choose “Colemak”
- Click “Add”
- Select Colemak as the default layout (or even better, remove the existing qwerty one)
- Click “Close” and you’re done.
The final production release of Hardy Heron is scheduled for April 24th. Hardy is also one of their LTS (long term support) releases, so it’s a pretty good time for Colemak to make its debut in a desktop OS.