I buy yet another gadget for my Macs.

I’d just finished writing the Networking chapter of my Mac OS X 10.4 Tiger: Visual QuickStart Guide when my editor, Cliff, called me into an iChat chat. Cliff and I often use iChat during the day to ask each other quick questions.

“Why didn’t you include AirPort Express in the book?” he wanted to know.

“I don’t have one of those,” I told him. Or at least I typed at his icon, which was a orange globe that day. “I can’t be expected to buy every piece of Apple hardware,” I added.

This was true. Every year, I invested hundreds, if not thousands, of dollars buying the Apple hardware I needed to write my Mac OS X book. A new desktop Mac every two years. A new laptop every three years. AirPort base stations and cards. iPods. Digital cameras, scanners, color printers. The list went on and on. It was very costly and I had a huge collection of old hardware that I just didn’t have time to put on eBay. Apple might help legitimate authors out with software, but it seldom coughed up hardware for the cause.

“But we should mention it,” he insisted.

“Do people buy it?”

“I’m sure they do.”

I switched over to Safari and surfed on over to the Apple store where I read a description of AirPort Express. Among other things, it enabled you to send iTunes data from an AirPort-equiped Mac to compatible stereo speakers. I thought about Mike and his desire to buy a new receiver. I looked at the price. Oh hell. What was another $129?

So I bought one.

It’s actually a pretty cool little device. It plugs into a wall socket and has three ports: USB, Ethernet, and Audio Out. You plug the Ethernet into a Mac, cable modem or DSL connection, or hub. (Mine isn’t plugged into anything.) You plug the USB into a printer, so the printer is accessible to users on the network. (Mine isn’t plugged into anything.) And you plug the audio out into a pair of stereo speakers or, in our case, a stereo receiver with speakers attached.

Then you configure the whole thing with the AirPort Setup Assistant. You have two options: configure it just so it sends iTunes to the speakers or configure it so it extends an existing AirPort network. I chose the second option. I mean, why not? And the iTunes to stereo thing still works.

It’s kind of cool to control the stereo upstairs with my PowerBook in the kitchen.

I’m impressed. I added a tiny bit of info to the book about it. But I’m also going to write an article about it for InformIt.com. That’s how I pay for this stuff, after all.