IGN and several other gaming sites have posted a twelve step program that Rockstar Games suggest you try if you have freezing issues with your Grand Theft Auto IV game.
You can find the steps needed at the following link.
Personally, when you consider the cost of a PS3 or XBox360 system, add the $59.99 cost of the game, I think all we should have to do is rip the cellophane off, open the plastic case, take disc out, insert into system..and finally PLAY.
But what they heck, at this point I will try anything. Don’t get your hopes up however, as initial reports show that these fixes did not work for most ppl.