Okay I hope that a mod will make this a sticky so that the information is right at hand for the people wanting to know where to find this software. I have also updated the links for the tuning software.
First off you will need to register at these sites to download the software need to reflash your ECU. Here is a list of the websites and what you will find there:
Main Page - OpenECU
---Here you will find the ECUFlash program to reflash your ECU
----Here you will find the cable and flash block(if needed) for reflashing.
Scoobypedia | Trusted knowledge for everything Subaru | Knowledge / Reading and Reflashing ECUs Using ECUFlash
---Here you will find the walk through to guide you through the reflash process.
RomRaider - Open Source ECU Tools | RomRaider / Rom Raider
---If you are feeling froggy enough to attempt to tune your maps yourself the goto this website for the Engiunity(which is now romraider) software.
Open Source ECU ROMS
---Here you will find the free stage maps, plus a XTP maps that you have to pay for.
Now this isn't a complete guide to this nor is this a complete list of the opensource software that is available, you have options this is just what I have used and if anyone would like to add to this list please PM me or add it in another post. If you have any questions please feel free to PM me and I will reply as soon as I can. Thanks again for reading this and I hope this helps everyone out.
Okay just to add this in here after reading a few post below(thanks dumdum and Lil Shoaf)Please remember to use caution when using these programs and what ever you do please ask all the question you must before tuning, it is easy to use yet also easy to nuke a motor all in one foul swoop. There are people on here, myself included, that are here to help you along as best we can. If you feel that you are not up to doing this type of reflash/tuning then please find another method until you feel comfortable with using this software. As another option if someone lives close by you that has experience with using this software ask them to show you how and teach you from there experiences. The best way is hands on. Okay enough blabaling for now.