This is how to do it:
* Quit the actual application.
* Right click the .app and select "Show Package Contents".
* Doubleclick the "Contents" folder.
* Open "Info.plist" in a text editor.
* Change
CODE
<key>LSUIElement</key>
<string>0</string>
to
CODE
<key>LSUIElement</key>
<string>1</string>
* Save file and exit.
* Done!

I can confirm its working for LaunchBar!