The MacBook Air doesn't have an optical drive, but it does have a new software feature called Remote Disk. This comes with every MacBook Air and works with both Macs and PCs. Simply install the Remote Disk software on the Mac or PC that has an optical drive and that drive will now be available to the MacBook Air. Slide a disk into the optical drive and Remote Disk shows up in the MacBook Air's Finder. Install software to your heart's content, but sadly you won't be burning CDs using Remote Disk.