Yes, Android handles multitasking and running applications in the background all on its own. It even does a pretty damn nice job of it. But sometimes, you want to have an app installed (Sprint Navigation anyone?) but hate the fact that it decides to start up and run for no good reason. Enter Autostarts.
Autostarts is an application watchdog. It knows when apps will try to start, why they want to start, and jumps in and blocks them from starting up and running. You do need to be rooted to use it, which makes sense as it's integrated pretty deep in the system settings. It's lightweight, very easy to use, and at $0.94 is a bargain for those obsessed with keeping apps behaving and following your rules on your phone.
Check out some more screenies and a quick walkthrough after the break
Fire up Autostarts and let it load. You can select each intent that would cause an installed application to start on it's own.
Open the category and pick an app you don't want to automatically run. Looking at you Sprint Navi!
If it's a system application, Autostarts will warn you about the consequences of blacklisting it
Click OK and BAM. No more crazy apps running at will.
Just be sure to use some common sense and don't block things you might want or need to run, and you're set. No more obsessing about background apps!