OK, I'm finally working on the PI loop tuning program. jyanof mentioned this program:
Kst - Browse Files at SourceForge.net
It graphs streaming data. So, here's my plan as of this morning. enter a proportional and integral gain constant through the serial port. Then, execute a new "run-pi-test" command through the serial port. That will load the array for Id (or Iq). Then, the array will output to the screen, which can be graphed by kst2 (link above). Repeat until your PI looop is tuned really nice!