Handy Light may seem to be a simple flashlight upon first glance, (and any subsequent glances) but it is secretly hiding a WiFi tethering app. AT&T charges around $25 a month for this feature, but you can have it for (almost) free! The app requires an iPhone with iOS 4 or higher.
Here is a video tutorial on how to get it working:
It is 99 cents, but will probably be gone any minute now. Get it while it’s hot!