Firstly, don't trust the Android built-in Battery Usage thing. It can be very innacurate. Use a third party app to measure CPU usage over time, such as "System Panel" (search on market). Secondly, is your GPS enabled? Search for "Dazzle" on Market, it's a free "Power Strip" widget that is much better than other paid power-control widgets. Turn off GPS to save battery.
In general, Android will cache applications in the background. If it is draining your battery, I assume you are on Eclair (2.1) and not Froyo (2.2)? Because Froyo is very good at handling "suspended" apps. Try these things:
1. Get "Autorun Manager" (Free) from the market. You can change which apps run at startup with this tool. But it only works for some apps, and usually not system apps.
2. Use Titanium Backup to "freeze" the application
3. Uninstall it
4. Get a "Task Killer" app. Note that Task Killers are BAD on 2.x Android, they can make your phone unstable if you kill something. I recommend "TaskPanel" (free) on the Market. Set all the system apps, such as Messaging/Market/etc. to IGNORE. But then set "Google Maps" to Autokill. This will make it so the app is automatically killed when the screen turns off. BUT THIS IS DANGEROUS AND CAN BE ANNOYING if you are actually using Maps!
5. Ask the people at xda-developers (search on their forum first), they are not a warez site but full of professional, you will certainly get more help there.
