I don't think you can, for an internal disk. For an external disk, just go to the manufacturer's web site, download the update program, and install it on the drive. The process is usually pretty straightforward - I've done it myself for a LaCie drive.
EDIT: My bad, that is for updating the drive's firmware. If you want to update the driver Mac OS X uses to talk to the disk, you can't other than installing new ones that come as part of a Mac OS X update (or rolling back a system to an earlier driver, which some Mac OS X 10.4.10 users did to resolve a USB problem).