Just because installing third party apps voids your iPhone warranty doesn't mean you shouldn't have fun with it! Signal is a cool little app that won't void your warranty and lets you control your iTunes library right from the screen of your iPod touch or iPhone.
Signal installs on your Mac, and starts up a little server that is accessible via the browser on your iPhone/iPod touch (or other device with a browser and internet access). Go to your special Signal URL and suddenly you have an iTunes remote control in your hands.
It is important to note that this doesn't stream your iTunes music to a remote device, it simply allows you to control iTunes (start, stop, and skip songs) from afar.
Signal costs $24.95, though a demo is available.