My phone (neo freerunner) has an arm4 processor, and it runs openmoko... but users in that community also run debian on it...
When I do work on it, I use ssh, so I can type on full size keyboard; and in the remote shell, I can mount the micro sd card, and can experiment with installing different os and custom kernel before booting from that card (it really is just a miniture pc
)
Being a slacker, I plan on trying to install armed slack (
http://www.armedslack.org/ ), but, being a slacker, haven't got around to her yet.