If you want to install the new OS X Lion on more than one Mac, a bootable installer drive can be more convenient than downloading several times.

Having a a bootable copy of the OS can also come useful if your Mac is experiencing problems.

Lion has a “Lion Recovery” feature but if you have issues with the HD, the recovery partitioner will not be available.

Here’s how to create a bootable USB or DVD

1. Download Lion and as soon as the installation is complete, exit from the installation prompt.

2. Go to your Applications folder, right click the Lion installation program and choose Show Package Contents.

3. In the folder that appears, open Contents, then open Shared Support. You’ll see a disk-image file called InstallESD.dmg. Copy this file to your Desktop or anywhere else it’s easy to access.

4. Launch Disk Utility (Applications > Utilities) and drag the InstallESD.dmg from the Desktop into the left-hand sidebar

5. Insert the USB (at least 4GB) or the DVD

6a. To create a DVD: Highlight InstallESD.dmg and click the “Burn” icon at the top

6b. To create a bootable USB: Highlight InstallESD.dmg and select the “Restore” tab in the main window.
In the Source browse for the InstallESD.dmg
In the Destination menu, drag from the left-hand sidebar the USB icon and select “Restore”