Apple has released an update for 15- and 17-inch MacBook Pro systems released in mid-2010, which addresses a problem that could cause freezes and hangs during use, and more notably during start-up. The prevalence of this problem is rare, but has affected a few systems.
In addition to the freezes and hangs, the update addresses compatibility issues with external displays.
In order to install the update, you will need to have your external power supply attached and should expect a gray screen with a status bar appear when the system reboots. It is important that you do not interrupt this progress bar during the update.
The update is available via Software Update, but also can be downloaded from the Apple Support Web site.
If the updater is not shown as being available in Software Update, then it is likely you do not need it for your system.
In addition to the firmware update, Apple has updated iWork, which addresses various small issues with Pages, Numbers, and Keynote. These are outlined in this Apple Knowledgebase Document.
The update should be available in Software Update for people who have iWork '09 installed, but can also be downloaded from Apple Support.
If you have any problems with these updates, please let us know.