I usually use mouses with wires, but a friend has a wireless mouse, happens to be a Microsoft mobile mouse 2000 but no doubt many are like this.
I'm not sure what it connects to though.
I am not looking at it at the moment.
I imagine it connects to some base, and then the base connects via USB, though the only base I saw was made by Belkin and was a 4 port hub, with a red light so it may have communicated with the mouse but I doubt it.
There's the mouse and there's the computer, there's a usb base. I can't see exactly what the mouse is transmitting to.