Same problem here. I just updated to 10.6.3 now 50% of the time after the MacBook Pro comes out of sleep the keyboard and mouse are frozen. There is no choice but to make a hard reboot. Before 10.6.3 I never had any problems with sleep, there is definitely a problem in the new update. Maybe they've been spending too much time on the iPad / iPhone and leaving us poor MacBook Pro users behind.
APPLE PLEASE FIX THIS IT IS A SERIOUS PAIN!!!!!!
The only way to make the computer usable is to not use sleep, meaning shutting down the computer everytime I want to move.