If you are like me and have installed Mac OSX Lion on a computer and need or want to create a bootable OSX Lion USB Drive, Apple have released an official tool to accommodate you.
Its pretty basic, download the tool, run the file inside the .dmg file and follow the prompts. You will need a 8Gb USB thumb drive (I believe 4GB won’t quite be enough). Now you can simply plug the thumb drive in, and on boot hold down the [option] key and select the recovery drive from the menu. I can verify that you can use this installer to create clean installs of lion without having to first install Snow Leopard and on machines other than the one that created the recovery drive.