yes it is expensive somethikng like almost $50 i saw here. you can't use a normal usb cable, you can even destroy the compuer. that's because some wires need to be switched between them.
the cable had something on the middle, it was very simple to use, it was plug and play, or as i like to say "plug and pray" plug it in the computer, install the software, and then you could use drag and drop to transfer the files. it wa quite fast. i rember that i transfered about 4Gb in about 20 minutes.
now i asked someone if i could use a normal cable, and they said that some mainboards have a chip called "computer to computer" or something like this wich enabled them to communicate using a simple usb cable with 2 connectors of the same type at the end.