[dTal]

Well, it runs stock Debian- so I imagine either the freesmartphone.org stack or oFono (both packaged), coupled with a relevant user interface. Really the UI is the hard bit, you can send and receive SMS just by cat-ing stuff to the tty device. Ubuntu has a lot of oFono-based UI stuff that can be stolen, though there's quite a few dependencies. Given how the Pandora community rallied around their platform, I've no doubt that we'll end up with a plug-and-play solution before long.

Also it'll probably be awkward for phone calls without some sort of headset (or just putting up with speakerphone all the time), but I hardly ever make calls anyway and it'll more than make up for that by being awesome at texting.