It's harder than it should be. If you do a regular MacPorts install it will crash because it doesn't have the ElemenTree module.
So here's a quick recipe using bzr source code:
sudo port install py26-celementtree py26-elementtree sudo port install py26-crypto py26-curl py26-distribute sudo port install py26-paramiko py26-pyrex sudo port select --set python python26 cd ~/src/bzr-2.4b5 python setup.py install --home ~/local export PYTHONPATH=/Users/ivan/local/lib/python export PATH=/Users/ivan/local/bin:$PATH
You should have a bzr that should be more usable than MacPorts. It's still not working for me as it takes 3G of memory, hits the swap and renders my computer useless.