There's tons of information on ECU tuning and ECUControl (Which is datalogging software and has it's own forum section) at
http://forum.pgmfi.org
There are no freeware editors that support the PT3 ECU, but they are tunable... If you really don't want to swap ECUs then you're pretty much stuck figuring out the PT3 code base for yourself... The people who have taken the time to figure it out won't spoon feed you the information you need to be able to tune it yourself...
