With Lion only available via the Mac App Store and Apple not offering the option of Lion on a USB drive until August (and at $69), how can you boot a machine from a Lion disc to perform a clean install? You can make a bootable DVD. Details inside.
Once you have the Lion installer downloaded from the Mac App Store (available here), to your Applications folder and right click or ctrl+click “Install Mac OS X Lion” and select “show package contents.”
Now open the “Contents” folder and then open the “ShareSupport” directory. Inside this directory you will see InstallESD.dmg. This is what you will need to burn to have yourself a bootable Lion install disc.
Simply fire up Disk Utility (/Applications/Utilities/Disk Utility) and then drag the InstallESD.dmg file onto the Disk Utility sidebar: