With the new iPhone adding applications, the iPod Touch got some of the app love as well. I just upgraded so that I could mess around with the new apps and found that Apple made a Remote app to control iTunes from my iPod via WiFi. So no matter where I am in my house, I can control my iTunes.
Ah, but you see I also have the Airport Express as my WiFi router. The Airport Express has a nice feature called AirTunes which will allow you to stream music from iTunes to it. The WiFi router has an audio out that you can hook up to, oh, say, your home audio system.
So, using my iPod to control iTunes on my computer that is sending the music to my sound system, I literally have music for the house at my fingertips. Crazy! Eat it, Jetsons!