Install adbWireless, available from the Android market. This application will only work on a rooted device (code for adbWireless is available on github).
From within eclipse, choose 'Help->Install New Software...' and select the site
http://ppareit.github.com/AdbConnect/ as update site.
Run adbWireless, there is also a widget available. Note the IP-address and port number.
(Re)start Eclipse. Select the menu 'Window->Preferences' and go to 'Android/Adb Connect'. Insert the correct IP-address and Port number. For instance as IP-address '192.168.1.103' and as port number '5555'. Choose 'OK' to close the preferences. There should be a toolbar with a button of a little Android with the body replaced by an antenna. Press the button, if the antenna goes from grey to red, connection is established.
You can mail me with any comment, suggestion or correction.