This is a clone of https://gist.github.com/244215 of to provide ZSH integration with git.
Example usage in .zshrc, assuming this is checked out to ~/work/zsh-git:
# Autoload zsh functions.
fpath=($fpath ~/work/zsh-git)
autoload -U ~/work/zsh-git/*(:t)
# Append git functions needed for prompt.
preexec_functions+='preexec_update_git_vars'
precmd_functions=(precmd_update_git_vars $precmd_functions)
chpwd_functions+='chpwd_update_git_vars'
# Use $(prompt_git_info) in your prompt and/or window title