Apple has released a firmware update that addresses a handful of issues on early 2009 Mac Pros. The update improves "compatibility with virtualization products utilizing VT-d, storage performance under Windows XP for Boot Camp users, and system reliability during the boot process." To install the update, follow the instructions in the updater application that launches automatically after the installer has closed (/Application/Utilities/MacPro EFI Firmware Update.app). More information regarding installing a firmware update on an Intel-based Mac is available on Apple's Web site. The update is available via Software Update and the Apple Support Downloads page. (Free, 1.96 MB)
Mac OS X Services in Snow Leopard
Mac OS X Services let one application supply its powers to another; for example, a Grab service helps TextEdit paste a screenshot into a document. Most users either don't know that Services exist, because they're in an obscure hierarchical menu (ApplicationName > Services), or they mostly don't use them because there are so many of them.
Snow Leopard makes it easier for the uninitiated to utilize this feature; only services appropriate to the current context appear. And in addition to the hierarchical menu, services are discoverable as custom contextual menu items - Control-click in a TextEdit document to access the Grab service, for instance.
In addition, the revamped Keyboard preference pane lets you manage services for the first time ever. You can enable and disable them, and even change their keyboard shortcuts.