Apple has released a firmware update for early 2009 Xserve models that improves "compatibility with virtualization products utilizing VT-d and system reliability during the boot process." More information regarding installing firmware updates on Intel-based Macs is available on Apple's Web site. Instructions for updating a headless (i.e. without monitor) Xserve are also available. (Free, 1.81 MB)
Mac OS X Zip Expanding Utility
Firefox (and possibly other applications) may ask you what you want to do with .zip archives that you download from the Internet. If you want to expand them with Mac OS X (rather than StuffIt Expander), you may be unsure of which application actually does the job. You're looking for Archive Utility (in Leopard and later) or BOMArchiveHelper (in Tiger). In either case, the application is stored in Hard Drive/System/Library/Core Services/. Don't move it from there, though, or you'll confuse matters.