This is a branch of MacVim 7.3 (from http://github.com/b4winckler/macvim/tree/macvim73) with a version of the vimshell patch applied.
It allows for a shell to be embedded inside a vim buffer: http://img.skitch.com/20100813-tqe3j411bjgfusbd413r2p8k1g.jpg

The patch is based on Eugeni Dodonov's (g)vim7.2 patch (http://aur.archlinux.org/packages/vimshell/vimshell/) which is based on Thomas Wana's original work (http://www.wana.at/vimshell/).

This branch is quite hacky, and lacks several key features:
  - support for text selection via mouse
  - support for copy/paste
  - support for ctrl+c
  - a scrollback buffer

This code is available here in case someone wants to work on it. However, I would recommend you simply use ConqueTerm instead (http://code.google.com/p/conque)