To connect a PS/2 model to USB, an adapter that does signal conversion works best: http://www.clickykeyboards.com/index.cfm/fa/items.main/parentcat/11298/subcatid/0/id/124184. I've been using these with three Model M's for years. I wish all of my equipment was as rugged as these keyboards. My favorite "Space Saver" Model M (no numeric keypad) has outlived many computers and will probably outlive me.
... but he still gets to use this bitchin' communication system supplied by The Shack for talking to the team director during a race (http://www.radioshack.com/product/index.jsp?productId=3247541). They'll tuck it in the rear of his time trial helmet.