File "/opt/local/lib/python2.5/httplib.py", line 1135, in connect
ssl = socket.ssl(sock, self.key_file, self.cert_file)
AttributeError: 'module' object has no attribute 'ssl'
The solution is to edit the Portfile (which lives in /opt/local/var/macports/sources/rsync.macports.org/release/ports/sysutils/duplicity/Portfile on my machine) and change "python25" in "python24" and halfway through the file change the py25- packages in py- packages. Then install the port. That fixes it.
Don't forget to not upgrade the port without changing the Portfile...