My favorite run-tracking app RunKeeper, in an effort to encourage more people to get off the couch, is making the RunKeeper Pro app (usually $9.99 USD) free to download now through the end of January!
The free version of RunKeeper is great by itself, tracking your run on a map using GPS and logging your speed, calories burned, pace, and all kinds of great information—which is also can automatically sync to their web site.
RunKeeper Pro adds customizable audio cues, advanced coaching, a complete range of activities to catalog, and you can easily see the difference by installing both RunKeeper Free and RunKeeper Pro and checking them out.