./smartctl -i /dev/disk0
smartctl 5.39.1 2010-01-28 r3054 [x86_64-apple-darwin10.4.0] (local build)
Copyright (C) 2002-10 by Bruce Allen, http://smartmontools.sourceforge.net
=== START OF INFORMATION SECTION ===
Device Model: Hitachi HTS545032B9SA02
Serial Number: 091030PBDC00QDKA2NHN
Firmware Version: PB3AC60T
User Capacity: 320,072,933,376 bytes
Device is: Not in smartctl database [for details use: -P showall]
ATA Version is: 8
ATA Standard is: ATA-8-ACS revision 6
Local Time is: Fri Jul 23 22:22:24 2010 EDT
SMART support is: Available - device has SMART capability.
SMART support is: Enabled
Power mode was: SLEEP this additional line
or
Device is in SLEEP mode, exit(2) this is displayed with --nocheck sleep | standby | idle