Hi, Errk! There are several apps that will do this. I used SuperDuper: it can create an exact clone, and it's a cheap app ($30 US, I think). You use SuperDuper to clone to an external drive, replace your laptop's internal drive, boot either from a Leopard CD or any external firewire system drive you have lying around with leopard installed, set up your new internal drive as a bootable system disc (either with Disk Utility or SuperDuper [as part of restore process]), and then run SuperDuper from somewhere and clone from your backed up clone to the new internal hard drive.
There are lots of websites and topics in forums detailing the process.
Good luck!