Right now, most of Apple's shipping computers come with Bluetooth as a standard feature. For all others, you'll need a Bluetooth adapter. Thankfully, they're both inexpensive and easy to install.
Currently-shipping Macs fall into one of three categories:
These Macs include a USB port, into which a separately purchased USB adapter may be plugged.
When purchased, this Mac can be upgraded to include an internal Bluetooth card. Unlike AirPort cards, the internal Bluetooth cards cannot be purchased and installed later. If you're buying a Bluetooth Ready Mac and you have any interest in using Bluetooth devices at some later date, consider upgrading to Bluetooth Included at the time that you order the computer. Otherwise, your Mac is equivalent to Bluetooth Optional, and you'll have to purchase a USB Bluetooth adapter.
An internal Bluetooth card is factory-installed inside this Mac.
If you have a Bluetooth Optional or Bluetooth Ready Mac, you'll need a USB Bluetooth adapter. There are a number of companies that sell them, including Belkin, D-Link, MacWireless.com, and Keyspan. The price is usually in the $40 to $50 range. There are only small differences between them; several different manufacturers sell adapters so similar that they're probably the same product with different branding.
It costs about the same amount to upgrade a Bluetooth Ready Mac to Bluetooth Included as it does to buy an adapter and add it yourself, so you might wonder why it would be worthwhile to skip it at the time of purchase. In our experience (as mentioned above), Bluetooth's flaky behavior can result in a number of problems. In several cases, what fixed the problem was removing and reattaching the adapter, causing the Bluetooth driver to reload. This isn't an option if your Bluetooth card is internal.
Our personal favorite external Bluetooth adapter was the D-Link DWB-120M (shown in Figure 6-1), because it's reasonably priced, reasonably sized, and it's the one that Apple used to recommend. This endorsement was important because applications aren't guaranteed to work with all adapters?having an Apple-approved product helped minimize incompatibilities. Unfortunately, when Apple shipped their Bluetooth keyboard and mouse, they stopped recommending the D-Link adapter, and it's incompatible with both peripherals. Our current recommendation: figure out which devices you're likely to use with Bluetooth, then research what adapters work with each.
The only Bluetooth adapter we actively dislike is the Belkin F8T003; it's almost twice the size of the D-Link and its flashing blue light becomes annoying after only a short time (and even worse, turning Bluetooth connectivity off on the Mac doesn't stop the flashing).
There's one other type of USB Bluetooth adapter, such as the Belkin F8T001, which is physically larger, more powerful, and has an antenna on it to allow longer-distance usage. Bluetooth normally reaches about 30 feet, and this higher-power unit allows a theoretical distance of up to 300 feet. We haven't found the extra distance to be worth the extra cost and the pain of the larger adapter; if you have a large office and need to sync your cell phone and your Mac from three offices away, you may find that it's worth it for you. However, your cell phone's Bluetooth range may not be great enough to even permit this!
Installing a USB Bluetooth adapter couldn't be easier. Find an open USB port on your Mac and plug it in. If you're using Mac OS X 10.2 or later, that should be the entire installation process. If you're running an older version of OS X, you'll need to upgrade. Bluetooth drivers are built into OS X 10.2, so you shouldn't have to install any other software.