Here’s a neat Android app that can save you money while travelling, or you battery life when you’re sleeping. It’s called APNdroid and it provides users with a simple interface to turn-off their data connection(s) when they want.
You can select which data connections you want to turn off — including GPRS, EDGE and/or 3G — and the best thing is that it can work as some kind of a homescreen widget, which is very handy for quick access. Once turned on (and data connections are turned off), you can still use your phone for basic phone functionality and rely solely on WiFi for your “Internet needs.”
As I said, APNdroid is free, so there’s no reason not to grab it. Bare in mind, however, when uninstalling it (if you ever need to do so), that you should do so while your data connection is working. Otherwise, the fake/non-existent Access Point Name the app uses to kill data will stick, and you’ll have to manually switch it back…