Yup, here's what you need:
Download the application from TunerCat's site.
PAy the license fee and get a serial number
Buy the correct definition file for the LT1 ($EE)-$20
Drop that file into the TunerCat directory on you computer
Buy the cable from Andrew at http://www.akmcables.com/
Now you are ready to read, edit and flash your PCM. IT's actually lots of fun. I still get the giggles like a little school girl evertime I do it.
Also download FreeScan. It's a great little program and is free to download and use. It has a dashboard screen that you can watch while the engine is running and see all the parameters that the PCM uses (Revs, inlet air temp, H2O temp, oil pressure etc etc...it's great) and you can see what trouble codes the PCM is throwing and reset them, which TunerCat cannot do.
http://www.andywhittaker.com/ecu/ecu_software.htm
Tim