Try iCal-Classic-Page-Flip (via MacUpdate):
iCal Classic Page Flip is a little SIMBL plugin for those of us who are frustrated by the very slow page animation in the latest version of iCal (the one that comes with Mac OS X 10.7 Lion). Both Monthly and Yearly views both have an animation of a turning page, which might be nice on the first look, but it's time consuming and slows down the work flow on the long run.
This software is the solution. It disables the painfully slow animation of the latest iCal version and gives you back fast navigation in iCal. Now again, you can use cmd + arrows to move to the next / previous month or year in iCal blazingly fast.
