Is their a gps computers to track in case the computer was ever stolen?

What is it called?
Where do they sell it?
Cost?

Thanks

There is not really a GPS system, but I think this is what you want:
Computrace LoJack for Laptops (http://www.absolute.com/products/lojack)

I have not personally used it, as my computer is so old nobody would carry it off.

Hope this helps,
WallyH