Does anyone know of a pc/mac compatable usb kvm switch box?

I want to do the following: -

Have both machines running then switch it across from the pc and use the mac, needs to be usb so i can use a usb keyboard and mouse (which the mac only supports)

Also, I am in the UK, please only post online shops which allow international shipping.

Regards,

David, on behalf of Skize Media (www.skize.com)