Although it is already possible to make a bootable restore medium of OS X Lion to use in case of emergencies, the process isn’t the simplest or most intuitive for all users. Fortunately, there’s a new app available called Lion DiskMaker which does the whole thing for you in just one click!
Lion DiskMaker is a fast and simple app that locates your Lion installer, and then turns it into your own bootable Lion Installer USB key! The whole process is quick, painless, and highly recommended.
You can find more information or download Lion DiskMaker over at the developer’s website.