KVM converter

I have two computers, a new dell with all usb ports and the mouse, keyboard and speakers with it running Vista home. I would like to to share the devices with an older computer that uses ps mouse and keyboard. I have its usb ports taken up with a printer and an external hardrive. That computer is running XP pro. I was looking at the IOGear with cable two port solution and the a converter to take the output of the one mouse/keyboard and attaching to a usb to ps for the xp machine - will this work and what are you suggestions.