it would help if you could either link to a site that lists all the output ports and/or interfaces on the skybox, or take a picture and post it. then i could give you links to the kinds of things you need. but if it has s-video, rca yellow-red-white, or antenna out, then it can be plugged into the eyetv 250, and the software that comes with the 250 will display it on your screen.
*****the 250 has all the same inputs on it as a tv does, so basically, how ever you plug the thing into your tv is how you will plug it into the 250, and the 250 plugs into your mac via usb2.*****