Like a lot of people, I struggle to get any decent battery life out of my Android phone (HTC Desire HD). I've tried so many different ways to make it last longer, but I've come to the conclusion that it's my need to have mobile data or wifi running at all times that hurts the most. I don't mind the idea of an app turning off data when I'm not using the phone BUT, I still would like to be notified of emails as they come in. So I was wondering if there's an app that would tie in with the GPS (I have Google latitude running all the time btw) and pretty much just turn off data when I'm in transit. Those are the only times I can't generally check my phone anyway so it makes sense that those are the times I'd happily try save some precious battery juice. It wouldn't even have to worry about wifi generally cos I'd be stationary when I'm using it, and there aren't any mobile wifi hotspots so just 3g data would suffice. or, another way to approach it, would be to set my phone to not allow data whilst roaming, and then have an app that forces my phone to GSM whilst traveling thereby saving even more juice. I dunno....just a thought as I do a fair bit of driving every day, and I figure the constant changing to different mobile towers whilst still picking up messages is wasting my battery.