The Win32/Cygwin version of 'hdparm' will tell you if you have HIPM or DIPM capabilities.

If you install Cygwin, or just grab the hdparm.exe executable with the cygwin1.dll, you can figure out if your hard drive/chipset supports DIPM and/or HIPM. DIPM is device initiated power management, and HIPM is host initiated power management. Both can cut down hard drive power usage which in turn can improve battery life on laptops.

Most likely your primary hard drive will be referenced as /dev/hda, so issuing 'hdparm -I /dev/hda' will return (almost) everything you ever wanted to know about your hard drive.

A cut-and-paste of part of my output from hdparm, with slight modification to not look so mangled in a blog entry:

/dev/hda:

ATA device, with non-removable media
Model Number: HTS541010G9SA00
Firmware Revision: MBZIC60R

o = Enabled
x = Disabled

o SMART feature set
o Security Mode feature set
o Power Management feature set
o Write cache
o Look-ahead
o Host Protected Area feature set
o WRITE_BUFFER command
o READ_BUFFER command
o NOP cmd
o DOWNLOAD_MICROCODE
o Advanced Power Management feature set
x Power-Up In Standby feature set
o SET_FEATURES required to spinup after power up
x SET_MAX security extension
x Automatic Acoustic Management feature set
o 48-bit Address feature set
o Device Configuration Overlay feature set
o Mandatory FLUSH_CACHE
o FLUSH_CACHE_EXT
o SMART error logging
o SMART self-test
o General Purpose Logging feature set
o WRITE_{DMA|MULTIPLE}_FUA_EXT
o IDLE_IMMEDIATE with UNLOAD
o SATA-I signaling speed (1.5Gb/s)
o Host-initiated interface power management
x Device-initiated interface power management
o Software settings preservation

I'm sure there are some other applications out there that will return the same information but I'm familiar with 'hdparm' and didn't want to dig through 20 pages of spec sheets to find the answer.