Same here. I have the same MBP from March and my system randomly tries to entertain me with a spinning beach ball for about 30 seconds several times a day. I hope they eventually come out with a fix ... or perhaps upgrading to Snow Leopard will be another option.
I bought my MBP in March, CTO with a 7200rpm drive - model ST9320421ASG. I've had this problem since day one, but this fix doesn't apply to this model drive apparently, despite the fact it was sold and installed by Apple. It's not showing up on Software Update, and downloading it and trying to install it manually gives me the message that this computer doesn't need the fix, same as others are getting.
This is seriously frustrating as I thought this fix would solve the problem.