While android might be really interesting, wouldn't it be cool if you could run debian on your phone? Well, it's actually pretty straight forward, since debian supports ARM natively. You install debian on your sd-card an chroot into debian, no dualbooting. If you want a desktop, you simply install a vnc-server, and connect to it via a vnc-viewer. You can do the same with ubuntu by the way.
More how-to here:
Chroot on android -debian.org
There is an interesting app in the market
that can install debian and ubuntu automatically for you.
Below is a video I found with debian/LXDE on an android phone.
(You can do something similar for Windows 95)