The Apple iPhone Remote application is described here:
http://www.apple.com/itunes/remote/Prequisites:
1. The latest version of iTunes. As of the date of this posting, that's iTunes 7.7.
2. Either an iPod Touch with the latest software upgrade, or the first generation iPhone with the latest software installed, or the 3G iPhone which already has the latest software installed.
3. iTunes on your Mac/PC registered/authorized with your Apple Store/iTunes account.
4. A wireless access point.
The Mac/PC that you want to control needs to be on the same network as the 802.11 wireless network that your iPhone is using. The remote control performs pairing, handshaking and command and control using the wireless network, so your computer with iTunes also has to be on the same network.
[ Note that this does not necessarily mean your (say) Macbook needs to be 802.11 connected. For example, if you have an Airport Extreme which is a home router, NAT, wireless access point, and 4 port ethernet switch all rolled into one, it would be sufficient to connect the Macbook to the Airport Extreme via ethernet, and configure the iPhone to connect to the SSID (802.11 network name) of the Airport Extreme. ]
Assuming all pre-requisites met:
1. Go to the iPhone main menu. Ensure that it is successfully using your home wireless network. If you are having trouble doing this, then refer to these documents (or PM me):
http://support.apple.com/kb/HT1355http://www.apple.com/support/iphone/internet/http://support.apple.com/kb/TS15592. Launch the AppStore application on the iPhone.
3. Search for "remote". "Apple Inc. Remote" should show up. Select it.
4. Once "Remote" application is selected, it should pop up another screen. Click on the button labeled "Free".
5. The "Free" button should change to "Install". Click on "Install" and it should start your download.
6. You may be prompted for your Apple/iTunes user account, which you should dutifully enter and proceed along.
7. Once downloaded, the application will install itself in the main menu.
8. Launch the "Remote" application from the main menu. The application should start ...
9. Select "Change Library"
10. Select "Add Library"
11. You will now be shown a 4 digit code. This is required for a successful initial pairing.
12. Open iTunes on your Mac/PC. The iPhone should show up in the device list of the leftmost panel of the iTunes Application window. If it doesn't show up, then there's something wrong with the network/host/iPhone configuration, or your wireless network is filtering broadcast messages.
13. In iTunes on the Mac/PC, select the iPhone, and there should be some selection that prompts you for the 4 digit code as per step 11.
14. And you're done!