Nike has updated their Nike+ GPS app to version 3.3 which adds some nice features...
★ Updates to improve compatibility and performance. We've integrated Tweet Sheet to make sharing on Twitter even easier.
★ Now you can choose to link to your route map or run curve when you share your run on Facebook.
★ Indoor/Treadmill runs can now run in the background on iOS 5. We've updated our engine to further enhance GPS and Accelerometer accuracy.
★ Fixed large game of Tag issues and general bug fixes.
Nike+ is a run tracking app that costs $1.99 to purchase and requires an iPhone or iPod Touch that is running iOS 4.0 or higher.