Can I first suggest the "Search this Forum" button which gives you:- http://androidforums.com/android-applications/292174-battery-saver-app.html http://androidforums.com/android-applications/263329-best-task-killer-app-battery-saving-tips.html http://androidforums.com/android-applications/225416-power-battery-saver.html http://androidforums.com/android-applications/213886-best-app-saving-battery-life.html http://androidforums.com/android-applications/21277-recommendations-optimizing-battery-life.html Hope these help.
Running a battery saving app on a constant basis is going to eat up more battery than learning how to do the same thing without to rely on an app. I have a Samsung Vibrant and I currently get around 35 hours on a single charge with moderate use. Here are some tips: 1. Don't use a task killer, they're bad for Android. Read this article to understand why. 2. Don't use widgets, I know they're handy but most of them are only for polling for information, which means they're constantly causing more of a battery drain. If you use apps that need to be refreshed, turn refresh off and refresh manually when you launch the app. There's no need in having several apps running and refreshing while you're sleeping. 3. Turn window animations off, all of that eye candy has to use more battery power than necessary. 4. Set your screen timeout to 1 minute or less. 5. Change your launcher/home app to something that is more resource friendly. The lighter home replacement apps are the best because they don't require as much in the way of system resources. I hope this helps.
Try Tasker. Steep learning curve, but it's really powerful. A couple threads on how to use it are here and here.