I saw Pact posted today, so thought I'd add Beeminder as well. They're kind of similar-- both track your progress towards your goals --the difference being that Beeminder isn't only for fitness.
Beeminder "makes the important urgent" by penalizing you (in rather alarming increments ;) ) if you stray off the track, rather than penalizing you on the deadline, if the goal hasn't been achieved. This ensures you actually do the small things every day that go toward gradual results, instead of procrastinating till the last moment and then rushing to complete it before the deadline.
Boss as a Service