The other is a more general 42.7 MB update for iWork '09. This is the second software revision for the word processing, spreadsheet and presentation package. The update says it improves reliability when saving some iWork documents. It also fixes some issues when Keynote sessions are played back multiple times.
Update: Users of Apple's pro video editing, photo and audio apps will also see the ProKit Update v4.5, which "improves reliability for Apple's professional applications and is recommended for all users of Final Cut Studio, Final Cut Express, Aperture, Logic Studio and Logic Express."
Your software update option under the Apple menu should get you one or all updates. The MacBook Pro update is a firmware update, and it will start up automatically after a download. If you don't see this update, your laptop doesn't require it.
Here are the included update instructions:
To update the SMC firmware on your MacBook Pro:
Your computer's power cord must be connected and plugged into a working power source.
1. Quit all other open applications.
2. Click Restart in the MacBook Pro SMC Firmware Update window and wait for your computer to restart.
The SMC firmware update starts automatically. A status bar indicates the progress of the update. During the update your computer fans will run at full speed, but will return to normal once the update completes.
Important: Do not interrupt the update.
Your computer restarts automatically when the update is completed and opens the MacBook Pro SMC Firmware Update.
3. Click OK. The SMC firmware is now up-to-date.
If these instructions appear on your screen again, the SMC firmware update was not successful. Repeat steps 2 and 3.
Thanks to Matt for the MacBook Pro tip!