I have a Motorola MC659B running Windows Mobile Professional 6.5 on it. I'd really like to have some variation of Ubuntu running on this device.
Can someone point me in the right direction?
The spec sheet (pdf warning) for the MC659B shows that it uses a Qualcomm MSM7627 CPU, a family that is well-suported by Android for mobile phones. CodeAurora seems to be running a project to further the Linux support for this SoC family.
It looks like the MSM7627 core was later included in the Snapdragon S1, so you might have a smooth time installing Linux.
Further specs show you get 512MB RAM/1GB Flash, plenty of space for a minimal OS. Have a a look at the BeagleBoardUbuntu project, because it contains a lot of good general info about running Ubuntu on a small ARM-based device.