Apple released its accessory to Time Machine today. It combines the Airport Extreme with 802.11n and a backup drive thats either 500GB or 1TB. You can wirelessly backup to the drive through Time Machine with any number of computers. Apple Insider has a great high-res gallery of it. You can buy it for $299 (500GB) and $499 (1TB) and it will be shipping in February. For more, visit Apple.