This is really simple if your phone is rooted.
Download a terminal emulator from Google Play (there are lots that are free). Make sure that your Android device is connected to your Wi-Fi and get the Wi-Fi IP address. Open the terminal program and type:
su
setprop service.adb.tcp.port 5555
stop adbd
start adbd
Now go to your computer (assuming that you are using Windows) and create a shortcut on the desktop for "cmd.exe" (without the quotations).
Right click on the cmd shortcut and choose "Run as Administrator"
Change to your android-sdk-windows\tools folder
Type:
adb connect ***wifi.ip.address***:5555
(example: adb connect 192.168.0.105:5555)
adb should now say that you are connected.
Note: if you are too fast to give the connect command it may fail. So try at least two times five seconds apart before you say this doesn't work.
