Simple PS/2 to serial adapter can work - but since they're electrically/mechanically only they require a PS/2 mouse that's compatible with serial. Plugging a non-serial PS/2 mouse might break the mouse and/or your miggy's serial port.
In addition, you'll need a driver to make them work as a mouse. There is absolutely no way to make them work on the normal mouse port without an adapter like alexh pointed out.
