I somehow missed the Ghost thread of Orac's link but I would have followed up Cornish Jack's reference to PowerQuest's Partition Magic.
It's good; it works. But it too is like a sharp knife and you must read up what you are doing carefully. The interface is all in Windows and is user-friendly.
Here's what I used it for.
The Sony notebook's 13GB HD was maxed-out with digital video files.
I removed the HD and put it in a caddy on a firewire link to the main PC with spare capacity.
Used Partition Magic (PM) to clone the boot partition of the Sony to part of the second HD of the big PC. The Sony HD was still intact and safe, of course. PM does this by creating the new partition "on the fly" even on a working partition.
Put new 40GB HD in the caddy and usd PM to clone the boot partition from the PC onto the new HDD.
At this point I missed a step. Tell PM to make the new partition "Bootable" or it won't boot when in the new host PC
After correcting my mistake above, took new HD out of caddy and reinserted into Sony laptop.
During boot-up, checked that the Sony BIOS HD settings were set to "Auto".
Sony booted just like it used to so I installed PM on the Sony and completed transfer of the second partition on the old 13GBHD. All this took about 4 hours.
Throughout, the original Sony HD was safe and if it went pear-shaped, I could always put it back. And there's still a copy on the Desktop PC.
Recommended for use on Win2K and ME; probably sound on the other OSs. But I don't like it for copying a working partition to another partition. It gets lost in trying to adjust the registry references from one Drive letter to another.