Look in the great finds section, there is a link to Lenovo for a belkin for $5.85. Works on my Model M keyboards, as well as everything else I've tossed at it. You could also search the wiki for "blue cube", which is bulky, ugly, and costs a bit more.
In the meantime, you could also go pick up the Dynex at best buy ($25) for use until your shipment arrives, if you're impatient. It had chatter issues at times though in Linux.
Good luck.
