./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