It all depends what you want. The consult Software Nissan use is available on the net but it's hard to find. There is plenty of other full on systems available that allow you to change parameters but they are usually expensive and need software dongles to work.
Then there is items like ScanGauge or other similar ones I can't remember the name of for anything from $50 to $200, they read error codes and shitloads more but don't allow you to make ECU changes.
Then there is the cheap Iphone type apps.
The cable is nothing special, there is a cheap ebay Bluetooth dongle or you can buy the cable with a multitude of ends on it for different readers.
Search either the net or this forum for things like "scangauge" "ECU reader" and "OBDII reader" you'll get so many answers you'll be able to make the most informed decision ever made.
check ebay worldwide for obd2, gives you pages of em, most are designed around the elm bluetooth and the torque app for your phone, which only give you realtime display of the data, but there are others,
