I know the remote app let's you connect to a computer on the same network and control the music on it, and even let's you choose the audio source (assuming you're connected to and airport/airport express with airtunes. And there's A2DP coming with iPhone 3.0. And now there's Airfoil which can stream music on a computer to the iPhone.
Now where is the App that let's me go directly from the iPhone to my wireless speakers on Airtunes??
Now where is the App that let's me go directly from the iPhone to my wireless speakers on Airtunes??