I'm posting this message using Firefox on Ubuntu. Well, at least virtually speaking.
I just installed 'VirtualBox'(open source software) that gives me the ability to run(or emulate?) a machine(computer) inside my OS, hence giving me the ability to run different operating systems and try them out.
I only installed it because I really wanted to try Ubuntu without too much hustle.
It's really cool though. I may not be able to run windows applications but if I had a notebook I'd definitely install Ubuntu on it :).
If the former, then you're pretty damn late to the punch man.
How awesome would it be to have a pocket pc with ubuntu on it though...