This is a neat idea, but it would be nice if the app used the phone's accelerometer to figure out the pace of your jogging, rather than making you figure that out on your own.
Match your music to your pace.
RunTempo changes the tempo of your music to match your running pace.
Select a speed in beats per minute, choose a playlist, and RunTempo will modify the tempo of each song to match your speed.
This free version is limited to 15 minutes of play time per day and is ad-supported. The full version is unlimited and ad-free.