Apple has announced that with the release of Mac OS X 10.7 Lion, the operating system will be available only via download from the Mac App Store. Past versions of the Mac OS X operating system have always been available for purchase on a bootable DVD. To create your own bootable DVD disc using your own blank DVD, follow the instructions below.
1) Purchase and download Lion from the Mac App Store on any Lion compatible Mac running Snow Leopard.
2) Right click on “Mac OS X Lion” installer and choose the option to “Show Package Contents”
3) Inside the Contents folder, you will find a SharedSupport folder and inside the SharedSupport folder you will find the InstallESD.dmg. This is the 10.7 Lion boot disc image.
4) Copy InstallESD.dmg to another folder like the Desktop. To do so, simply click and drag the file to the desired location while holding down the Option key.
5) Launch Disk Utility (/Applications/Utilities).
6) Click the Burn button in the upper left corner of the Disk Utility window. Select the disk image InstallESD.dmg and click the Burn button. A burn dialog will appear. Insert a blank 4.7GB DVD and click the Burn button.
To boot from the DVD, simply insert the disc and hold down the Option key while your Mac is booting up. A screen will appear asking you which volume you would like to boot the system from. Click on the OS X installer DVD and the system will boot using the disc.