If you've read our guide to building a Hackintosh you know that installing Mac OS X Lion requires a bit of work. You have install Snow Leopard, then go through a fairly tedious upgrade process rather than just installing from scratch. Fortunately, thanks to a new utility called UniBeast (from tonymacx86, of course), that's no longer a problem.
UniBeast not only allows you to create a bootable Lion flash drive for a Hackintosh, but it also removes the need to use an iBoot CD to boot. This mean you no longer need an optical drive to create a Hackintosh. All you need is a copy of Mac OS X Lion — from the Mac App Store or on a retail USB drive — and an 8GB flash drive of your own. You format that drive with a single partition with a Master Boot Record partition scheme. Once formatted, you run UniBeast and it will take care of all the magic for you. When it's done, you'll be able to boot from it and install Lion. (Note: some extra boot flags may be necessary in some cases, depending on your setup.)
Once Lion has been installed, you'll still need to run MultiBeast to add drivers and other configuration options to get your hackintosh running smoothly but this process will save plenty of time. Check out tonymacx86's UniBeast installation instructions for the detailed run-through. They're very thorough and will put a bootable Lion flash drive in your hand with hardly any effort.
UniBeast: Install Mac OS X Lion Using an All-In-One Bootable USB Drive [Tonymacx86's Blog]