A friend of mine started up a website where you try to walk a mile a day (or more, whatever you want) that seems to be a really positive take on the whole "eek! New Year's fitness resolution" thing many of us go through. Take a gander, join if you'd like - I'm on there (as oceanpony, natch). I think it'd be cool to note that, at the end of '08, you've walked at least 365/6 miles...
1x365 - Run, Jog, Walk