How do I install Homebrew on Tiger?
So, I finally managed to have a working version of homebrew, but it wasn't that simple.

First, download from sources and make install of Git following these instructions.

Then, using git, get the sceaga Tiger branch of Homebrew.

All should then work correctly (more or less).

EDIT There seems to be a tarball hidden somwhere that could be used with root installation procedure. It has the obvious interest of avoiding one to install git just for the sake of having a running homebrew to ... install another git version.