Apple’s latest OS update — 10.5.5 — is now up and available for download from Software Update. It’s a big update and includes lots of changes. Usually Apple’s release notes border on monosyllabic grunts but this one is quite detailed. Scanning through them revealed these below that I’ve found interesting.

• Improves Spotlight indexing performance (always good)
• Improves iPhone sync reliability with iCal and Address Book
• Improves overall sync reliability for MobileMe
• Time Machine can now back up iPhone backups that are on your Mac, as well as other items in ~/Library/Application Support

For more details, check out the accompanying support notes on Apple’s website.