Cloning an hard disk to smaller hard disk

As the title says, I have 2 hard disks, source disk is 10GB with 4.5GB used and target is 8GB. The only partition on the first hard disk is a NTFS partition with Windows XP SP2 on it.

I’ve been using dd if=/dev/hda of=/dev/hdb under linux for situations where the source and target hard disks were identical in size without a problem, but what should i do in this situation ?