Unfortunately, the Maemo/Meego/etc. OS family from Nokia is not completely open-source, and as such, has not been ported to non-Nokia devices (so far as I know).

I'm afraid it'll be a lot of work to port Linux to your tablet by yourself, especially if you're completely new to the Linux world. However, let me point you to the Jlime project. That's the version of Linux I used on my HP Journada (another Wince device), and they're currently porting the system to the Raspberry Pi. I suspect they would be able to give you a better answer as to how (or if) you can get a Linux distribution onto your machine.