Colourised git-aware PS1 that also knows what repo you're in.

gistfile1.txt

__git_repo () {
  local g="$(__gitdir)"
  local repo_dir=""

  if [ -n "$g" ]; then
    if [ ! ".git" == "$g" ]; then
      git_dir=`dirname $g`
      repo_dir=`basename $git_dir`
	  printf " $repo_dir"
    fi
  fi
}

export GIT_PS1_SHOWDIRTYSTATE=1
export PS1='[\[\033[0;31m\]\u@\h\[\033[0m\]\[\033[0;36	m\]$(__git_repo) \[\033[0;34m\]\W\[\033[0;35m\]$(__git_ps1 " (%s)")\[\033[0m\]]\$ '

I use this on my mac. You'll also need the git bash_completion stuff enabled (e.g. 'source /usr/local/git/contrib/completion/git-completion.bash')