Apple has rolled out Mac OS 10.6.3 upgrade for Mac OS X Snow Leopard users. This new upgrade includes many bug fixes of the previous version Mac OS 10.6.2.
So, the users who are running Mac OS 10.6.2 can grab the new update automatically just through navigating to Software Update from Apple menu, or by visiting the Apple page manually.
Mac OS 10.6.3 Fixes & Improvements List
General OS Fixes and Improvements:
Performance of Logic Pro 9 and Main Stage 2 when running in 64-bit mode.
Sleep and wake reliability when using Bonjour wake on demand.
A color issue in iMovie [...]