I recently replaced a well-used PowerBook G4 with a new MBA that came with Lion pre-installed. If anyone else is planning this or trying to do the same, here's what I found out: 1) The Leopard to Lion Migration Assistant (currently version 1.2.3) only works with Intel Macs. There may be an update sometime that will allow PPC to Lion but no guarantee. 2) If you have a Time Capsule backup, it will only restore to a similar machine. Attempting to reboot the MBA using command-R will only bring up a dialog that states that. 3) The best option I found was to buy the $29 USB to Ethernet adaptor for the MBA and then drag and drop the documents folder, iPhoto folder, etc. Hard to believe it is that difficult to configure the migration assistant to capture the essentials of a move but the worst part of this was that it took the Applecare rep 15 minutes to figure out number 1 and then the local genius bar advised doing number 2. Save yourself some time and follow option 3 and you'll be up and running faster.