sudo apt-get update && sudo apt-get upgrade

Update:

As you may know, there were some issues with Intel Graphic Card drivers (965: x3000 or x3100) in Ubuntu after the upgrade to Jaunty - desktop effects could not be enabled - so you could not use Compiz and other applications that needed it.Well, it seems that after today's or yesterday's updates (or something like that), Compiz works again with some Intel video cards. My girlfriend has a Dell Inspiron 1525 which comes with a Intel Graphic Card X3100 on which Compiz now runs ok.So you can try updating and see if yours works too (if so, I would appreciate some comments with your computer's specs, so other people will know it will work for them too):You may also want to check out the Ubuntu graphic drivers repository