I use the Tactrix cable to make the connection from the laptop to the ECU. I recommend purchasing it through our sponsor Lloyd at www.TunerTools.com. If you're a member of www.racevideoforums.com enter promo code RACEVIDEO and get 5% off. You can also get it from www.Tactrix.com (no discount)
I use ECUFlash from www.openecu.org to download the stock ROM out of the ECU and to flash my custom ROM. It's free and works on EVOs and Subarus for adjusting the fuel and timing maps.
I use Evoscan to log variables like RPM, Timing, Knock, Narrowband 02, LoadCalc, TPS etc.. you can get it here http://www.limitless.co.nz/evoscan/ There's also a free alternative that doesn't have all of the fancy gauges called Mitsulogger and you can get it here www.aktivematrix.com
I just shot some video of me demonstrating how to connect the Tactrix ODBII cable, download the stock rom with Ecuflash, log with Evoscan and upload your new Mellon Tuning flash file. I had a cold and sound kind of nasal so don't laugh :)