While Leapard users are waiting (im)patiently for SuperDuper ver 2.5 to be released, be aware that existing functionality built into Disk Utility allows you to clone a volume to a sparse image file and restore from same.

Two important details to be aware of:

(1) If you are archiving your HD, you must boot from either another volume or your Leopard DVD.

(2) When restoring to your HD, of course you must be booted as per the above; and also you must first erase the destination volume. Disk Utility appears to allow an integrated erase/restore operation, but there's a bug here.

Missing, of course, will be SuperDuper's ability to create a bootable clone, a customizable clone, a smart-updateable clone, etc.