Apple has updated Snow Leopard. It's recommended (if you aren't running a hackintosh with an Atom processor. It will break that.)

The 10.6.2 Update is recommended for all users running Mac OS X Snow Leopard and includes general operating system fixes that enhance the stability, compatibility, and security of your Mac, including fixes for:

• an issue that might cause your system to logout unexpectedly
• a graphics distortion in Safari Top Sites
• Spotlight search results not showing Exchange contacts
• a problem that prevented authenticating as an administrative user
• issues when using NTFS and WebDAV file servers
• the reliability of menu extras
• an issue with the 4-finger swipe gesture
• an issue that causes Mail to quit unexpectedly when setting up an Exchange server
• Address Book becoming unresponsive when editing
• a problem adding images to

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On the heels of the 10.5.8 update, Apple has added Safari 4.0.3 to that list, citing the following:

This update is recommended for all Safari users and includes improvements to stability, compatibility and security including:

• Stability improvements for webpages that use the HTML 5 video tag
• Fixes an issue that prevented some users from logging into iWork.com
• Fixes an issue that could cause web content to be displayed in greyscale instead of color

In depth (as in depth as Apple gets...) information can be found on Apple's website.

http://support.apple.com/kb/HT3733

Run Software Update to download the latest version.