(Linux and Mac)
You will need Apache Ant and Git.
Run: git clone git://github.com/TomyLobo/ccnoise && cd ccnoise
It should download the repository and cd into the repository.
Next, run: ant
It should find the Buildfile and start downloading Forge and MCP.
It will start decompiling Minecraft and then after a few minutes there should be a file called 'ccnoise-VERSION.jar' in build/dist. That is the compiled version of ccnoise.