Installing SIP on Mac proved to be a tad difficult with this error message
$ sudo port install py-sip
---> Activating python24 @2.4.6_0+macosx Error: Target org.macports.activate returned: Image error: /opt/local/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4 already exists and does not belong to a registered port. Unable to activate port python24.
So, I removed the whole directory:
$sudo rm -rf /opt/local/Library/Frameworks/Python.framework/Versions/2.4/
and then installed py-sip