Startup Control Panel, by Mike Lin, is a nifty [freeware] control panel applet that allows you to easily configure which programs run when your computer starts. It's simple to use and, like all my programs, is very small and won't burden your system.

StartupMonitor is a small freeware utility that runs transparently (it doesn't even use a tray icon) and notifies you when any program registers itself to run at system startup. "