Can & How Can I Install Windows 7 x64 on a MacBook Air?
EDIT: You don't need a SuperDrive, any External Optical Drive will do. I have a SuperDrive and a Buffalo External Drive. I do not recommend buying a SuperDrive EVER; as other drives suffice, and if you ever have issues with a bad boot sector (as I have) you cannot boot from the drive and use an external HDD to copy your data off the internal HDD.
Apple does not support x64 on a MacBook Air, but you can, and I have installed Windows 7 x64 Home Premium.
You will be asked to install a 32bit Version of Windows; which I ignored, following Gizmodo's Install Guide
Upon a subsequent install, running setup.exe directly will not work because Apple has disabled it for the MacBook Air, running it results in ...
"Boot Camp x64 is unsupported on this computer model"
... but being unsupported doesn't mean it doesn't work! :)
Issues to resolve are that you will require a two button mouse or keyboard with a right click equivalent, the latter being my solution to get to the menus.
Use "Compatibility Mode" to install:
<optical-drive-letter>:\Boot Camp\Drivers\Apple\BootCamp64.msi.
Friends of mine run VMware fusion and are very happy with Windows 7 on that, I think they are running 32-bit editions but I did see this post that says that 32-bit and 64-bit editions of Windows 7 Beta were supported on VMware fusion so I'd suspect it should handle the released version on Windows 7 64bit