Funkstille disables WiFi and Bluetooth when you don't need it. Bluetooth can be disabled if not connected to a power cord (carkit). WiFi can be only enabled when the device starts roaming and a 3g connection is not available. Both features can be configured separately.
I created this application because I only use bluetooth when I am charging my phone in my car and want to connect to the carkit. I travel abroad almost daily. While abroad I can only connect to the internet by WiFi. And, I don't need this WiFi connection when the phone is not roaming. That's why I disable it in that case. These measures make my phone use a lot less power and help it survive quite a bit longer.
As well, this app is the first Android app I developed. I used it as a means of learning the basics of Android development. I hope some of you actually find a good use for it (as I do, BTW). Feature requests are welcome. sourcecode will be shared on request.