These tools are a work in progress. They currently support reading, writing, and data logging with General Motors P01, P10, P12 and P59 Powertrain Control Modules (PCMs).
Go here: https://github.com/LegacyNsfw/PcmHacks/releases
The most recent release will be at the top of that page.
Click "Assets" (below the description of the release) and download the .zip file.
Extract the contents of the zip file, and run PcmHammer.exe or PcmLogger.exe.
The GM section of pcmhacking.net
A shortcut to the project's GitHub page
Most people use tunerpro. To do so you need to know the operating system id of your computer (OSID) and use that to find a matching XDF file which tells tunerpro what is in the XDF and how to edit it. XDFs can be found on pcmhacking.net and other places. Also check out Universal Patcher which does a lot more than just patching!