Christian put together an excellent guide on setting up an Eclipse IDE for Maya python development etc. http://tech-artists.org/forum/showthread.php?t=1052. Among other processes, the guide details the steps needed get Pyqt and Maya playing nicely with one another.
Based upon the error that you’re seeing, I suspect that something is amiss with your Pyqt installation. I think I initially ran into a similar issue myself, and if I recall correctly, it may have been related to the following step:
“Replace the sip.pyd with the downloaded one”.