Advice on Cloning Hard drive for upgrade

Hi All,
I have had a less than pleasant time with having upgrading my Logic Pro 8 to LP9 so now that I'm considering upgrading Leopard to Snow leopard, I think I will take the precaution of cloning to another hard drive and performing the upgrade on the clone.
What I want to know is can I avoid nightmares with reauthorising the huge list of AU's I have? A lot of my stuff is on iLok so that's fine, but will all the stuff that just authorised with serial numbers etc, need reauthorising? If the mac itself is the same and I use some particular cloning software, can I avoid the need to reauthorise and do I need to use the same model and size of hard drive to achieve that or can I clone to a bigger one, for future proofing?
Many Thanks in advance for your help :)
Yes,of course you can move to bigger drives.That's the way to do it :)
Just try it out and you'll see it's easy,absolutely trustworthy,simple.
I'm going to be doing the same thing this week after my new 1tb drive arrives today. I plan on partitioning the new drive, cloning my current drive twice, to each partition, then upgrading one of the partitions to snow leopard. I'll be taking out the original drive as my mac is filled up. I'll be putting the original drive in an external enclosure and eventually will reformat it and use it for something else after things seem safe. I also use superduper and it seems to be fine with most authorizations. I'm curious how one uses disk utility to clone a drive?
No, I mean Partitioning and cloning can be done with Disk Utility.
The simple way to clone a drive is to use the "Restore" function in Disk Utility. Just choose the source and destination. If you want the clone to be bootable select "Erase Destination - Erase destination and Replace with contents of Source." The underlying tool that is used is called 'asr' (Apple Software Restore) and I believe that SuperDuper uses the same thing.
Also forgot to mention that if you're cloning your System drive then it may be a good idea to boot from the OS install disk and use Disk Utility from there. It usually goes faster that way.