Most new HD's will come with a disk manager software (In fact WD drives call it disk manager).
Included in this software is a utility to take the image off of your old one and place it on the new one. (which is the useual purpose)
And, if you don't have issues copying files in use, (I didn't) you can drag, drop (Have to have hidden files showing though) in windows explorer in 95 or 98, don't know about Mil, 2k, or XP.
(Really, it works! Have hooked up new drives and imaged them with my original one that way.)