Is the MacBook Air "MagSafe" power connector also compatible with the MacBook and MacBook Pro?

No. The MacBook Air "MagSafe" power connector only provides 45-watts of power, and as such, cannot power the MacBook (60-watts) or the MacBook Pro (85-watts).

Additionally, the "MagSafe" power connector for the MacBook Air is rotated 90-degrees to save space. The "regular" MacBook "MagSafe" power connector will provide power to the MacBook Air, but it won't fit when the MacBook Air sits on a flat surface.

Does the MacBook Air really not have an Ethernet port? How can you connect to wired networks?

The MacBook Air really does not have an onboard Ethernet port. Apple instead offers an external Apple 10/100Base-T Ethernet adapter that connects via the sole USB port on the MacBook Air for US$29.

Those who require Gigabit Ethernet capability -- or who are disinterested in carrying an adapter to connect to wired networks -- would be better served by a MacBook or MacBook Pro.

Is an external modem available for the MacBook Air?

Yes. Just like all the other Intel-based Macs, Apple does not offer an internal modem with the MacBook Air. An external Apple USB Modem (56.6k v.92) is available for US$49.

What is Bluetooth? What is the difference between Bluetooth 2.0+EDR and 2.1+EDR?

For those who have yet to use the ubiquitous Bluetooth technology, Apple reports that it is an:

Open specification that enables short-range wireless connections between desktop and notebook computers, personal digital assistants, mobile phones, camera phones, printers, digital cameras, keyboards and even a computer mouse. Bluetooth wireless technology uses a globally available frequency band (2.4GHz) for worldwide compatibility.

In a nutshell, Bluetooth technology unplugs your digital peripherals and makes cable clutter a thing of the past. . . You can link your Palm OS-based handheld device, mobile phone and other peripherals with Bluetooth technology -- and do it wirelessly, within a 30-foot range.

Bluetooth 2.0+EDR and Bluetooth 2.1+EDR are quite similar, but the newer 2.1+EDR standard offers improved security, "pairing" (meaning that it is simpler to connect devices to one another), and power optimization.

For more details regarding Bluetooth 2.1+EDR, please refer to The Unwired and GearLive.