How can I get Linux on a T-Mobile phone? Answered

     I have an old T-Mobile Dash cell phone.  I want to run some form of Linux (or another open-source OS) rather than Windows Mobile.  I want to be able to do open-source voIP, text, etc.  I also want to be able to use T-Mobile's supposedly excellent international coverage (I'm going to England).  The phone can connect to a computer and has a microSD slot.  Any recommendations are welcome.  Thanks!

P.S.  I heard that I could partition off part of the microSD to use as extra RAM.  How do I do this?

I'm also thinking of toughening it up to survive drops, falls, water, etc.  Any recommendations as to what to do for that are appreciated.