As usual, not a lot given away by Sony on their website or their manual.
If you're likely to have to replace it anyway, do you feel brave enough to take it out and have a look? If there's lots of pins at the end, it's IDE. If there's a couple of L-shaped connectors, it's SATA.
Or do this:
Go into Device Manager:
Right-click My Computer > Properties > Hardware Tab.
Click the + next to Disk Drives.
What does it list the hard drive as?
-------------------- OK OK I can't go any faster! aaaaaaaaaaaagh!