I downloaded the software but ordered the cable from Accel. Here is a page with the info about which one you need:
http://www.accel-dfi.com/pdf/Pages32_33.pdf
I've not been able to find the place that I ordered it from. But I've since found you can get the "cable and USB Key" from Summit Racing. I think this is the one:
http://www.summitracing.com/parts/AC...5&autoview=sku
(This includes a DB9 connector to the wide band controller which is not used in some applications.)
I got the Pro key/cable since I'll be turning the system over to a tuner to do the work.