If you haven't installed homebrew yet, it a useful tool to have. Google it, it will be fast.
brew install python3
/usr/local/share/python3/easy_install pip
ln -s /usr/local/share/python3/pip /usr/local/bin/pip3
I'll install Jinja2 for testing
pip3 install jinja2
Use python3 to execute them of course :
python3 myscript.py
By vinyll on May 1, 2012