Homebrew consists of a git repository which has "recipes" for how to install certain software. Basically like NetBSD pkgsrc, Gentoo's portage or Archlinux PKGBUILD. Luckily, these scripts are super-easy ruby scripts which can be commited to Homebrew through Github pull-requests. I myself recently added two packages and another one way back (tho not through a pull-request doh).
So that's me for tonight, i'm back from my vacation, so expect some more content soon. Also, i am planning on moving this Blog once and for all away from posterous, as the performance seems really bad.