Using the AutoCAD License Transfer Utility
Starting with AutoCAD 2010, the old Portable License Utility (PLU) has been replaced by the License Transfer Utility (LTU). The old PLU essentially created a "license file" that you could move from one computer to another using a network, flash drive or any other method. If you bought a new computer for example, you could install AutoCAD on the new computer, and use the PLU to transfer the activation from the old machine to the new one.
The only problem with this is that the PLU failure rate was about 50%, and because you had to define the target machine when you exported, you could not re-import back onto the same machine.
So along comes the LTU. So what is the difference? The LTU copies your activation up to the Autodesk servers where it can sit until you are ready to import it. So far in my testing, it has not failed once. Of course you will need an internet connection on both machines, and you will need an Autodesk UserID and password. If you don't have one, you can create one.
Exporting a license
The first step is to launch the LTU. It's on the Start Menu in the same program group as your application. The initial dialog will look like this
Click the Sign In button. After you have signed in (or created a new account and signed in), the next dialog will look like this:
By default, you will only be able to import this license to a machine with the same serial number and the same Autodesk account. If you check the "Make the license available as a public import", then anyone can import the license. The AutoCAD install will still need to be done with the same serial number as the install from which the license was exported.
This next screen is confirming that the license was exported successfully.
Importing a license
Now you are ready to import on a different machine. Remember, the second install must use the same serial number. Start the same application (LTU) on the second machine, and after you log in, the license importing process will begin.
After this has completed, a confirmation dialog will appear letting you know that the license was imported successfully.
I have only tested with multi-seat standalone licensed AutoCAD based products, but it should work the same way with single seat licenses also. Of course there is no need for this utility with network licensed AutoCAD.
Update (2009-09-21): Autodesk has uploaded a how-to video to Youtube on this same topic. I have not watched it all the way through, but if you have 15 minutes, I'm sure it's good.