Auto3G is a new tweak available in Cydia that will help you extend battery life during daily use by automatically disabling the 3G connection when you are not using the phone. We all know that using the phone on the 3G network leads to much higher consumption than in the case of using it on the EDGE/GPRS network, so disabling 3G can dramatically improve battery life. Auto3G automatically deactivates 3G when you lock the phone and automatically reactivates it when you unlock it, so you don't even feel the lack of 3G connectivity. Auto3G does not currently work with the iPhone 2G because it does not have a 3G chip in it.
Auto3G is available in Cydia, but it also has a reasonable price, so if you want to install the application, you have to pay $5.99.
