Sleep Timer for Android makes it easy to stop nearly any media app after a user-specified amount of time–perfect for turning your tunes off before bed or timing a power nap.
Sleep Timer is different than most similar apps in the sense that it is not a media player itself; Sleep Timer is a tool you layer over your existing media applications. Sleep Timer is compatible with nearly every sort of Android-based media application you can throw at it. You simply install Sleep Timer, pick the application you want to control, set the timer, and specify the command you want Sleep Timer to push to the app (such as pushing the Pause command to your SlingPlayer).
Sleep Timer is a free application, requires Android 2.1+.