Display current Git branch and root directory in Mac OS X Terminal title bar.

.bash_profile

# Add to .bash_profile

parse_git_branch() {
    git branch 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/ (\1)/'
}

get_git_root() {
  basename $(git rev-parse --show-toplevel 2> /dev/null) 2> /dev/null
}

update_git_prompt()
{
	GIT_BRANCH=$(parse_git_branch)

	if [ -n "$GIT_BRANCH" ]; then
		GIT_ROOT=$(get_git_root)
		echo -ne "\033]0;$(get_git_root): $(parse_git_branch)\007"
	else
		echo -ne "\033]0;\007"
	fi
}

PROMPT_COMMAND="update_git_prompt; $PROMPT_COMMAND"

Works also on Linux. Must have for multi-project environment.