Our own former C.K. Sample III turned us on to some more sleeper features of Apple's quietly-introduced AirPort Extreme. Specifically, that new USB hard drive sharing feature is called AirPort Disk, and it has a few tricks up its sleeve. First, it can share a drive with both Macs and PCs, but its setup utility can easily set the drive to auto-mount when you login or start up your machine. Not content to stop there, however, you can even set up individual accounts for each machine on the network with access to only specific files or folders. Not bad for a $179 device.