I've always thought that Android should give you more control over how long Wifi and 3G stay connected after you turn the screen off. Sometimes its nice to keep them on while downloading something, but it bugs me when Spare Parts tells me that my Wifi is on for hours longer than my screen is. DataOff is an app that gives you more control over the delay before Wifi (3G coming soon) turn off when the screen goes off and come back on when the screen turns on. The source code is available here so developers send me an email and I'd be happy to make you a member of the project. For the less developer-savvy, I've posted the latest .apk, leave me some feedback/love/hate.