well, you can do it with a hotkey, but I'm not sure if that's exactly what you're trying to do. why don't you try to explain better. would you be using it through lsxcommand, or in a popup, or as a hotkey, or what? in the meantime, here's a stab in the dark.
as a hotkey:
*hotkey CTRL Z "http://www.yahoo.com"
in a popup:
*Popup "Test" "http://www.yahoo.com"