Has anyone replaced the mechanical momentary switch found on PCs with an electronic version.

I want a PIC to be able to control the momentary action of this button.

The voltage across the header on the motherboard is around 3.17 volts, but i want the PIC to be a mechanical replacement where it then doesn't matter about the polarity etc on these motherboard pins.

What would be the best method of creating this switch, preferably without using a relay.

Cheers.