Put working git branch in shell prompt for bash and zsh?

[Craig Rodrigues]

Hi,

I am heavily using git for my projects these days.
Typically I am working on multiple projects, with
multiple checked out trees.  I am also switching
between branches a lot.

Sometimes because I am working with so many
checked out trees, I lose track of what branch
I am working on.

Can anyone point me to a "stupid shell trick"
which would put the currently active branch in the
shell prompt?  I typically use bash and zsh shells,
so having the trick for those shells would be useful.

Thank!

--
Craig