(FORTUNE Magazine) – Wireless rocks! Wireless stinks!

As usual with an emerging phenomenon in the computer industry, both statements are true. This specific wireless phenomenon is called 802.11, the number the engineers who designed it assigned to it, or WiFi, the name the marketing people prefer. What it is is a small card for your notebook computer that connects it wirelessly to a local network. The card has a radio in it. What's special about these cards, in theory, is that a card made by one manufacturer will talk to a card made by any other manufacturer.

I've been using wireless networks for about six months now and can report that WiFi deserves every bit of hype it has won. But this technology is not ready for prime time. And the bit of prime time that it is least ready for is the most exciting stuff, called public access wireless.

Wireless networking is a phenomenon for one simple reason. When you don't have to plug in anywhere, you are truly mobile. You can carry your computer from one place to another and still be connected to a network. Yes, that's great at home or at work. But it's even greater anywhere else you might carry a computer: airports, hotels, other people's offices, even a coffee shop or restaurant.

As usual in the computer business, the visionaries have been hard at work, so there are some pretty alluring ideas floating around about what might happen if wireless networking were ubiquitous. For instance, a dream of the computer industry is devices that are able to talk to each other without us humans having to tell them what to do. With wireless networking, a notebook computer might be able to discern on its own that it's near a network access point and connect to pull down your new e-mail. Imagine: As you run through the airport to catch a flight, your computer picks up the latest e-mail. On the plane ten minutes after takeoff, you pop open your computer and work with your most recent messages.

That's just e-mail. With wireless networking, your PDA might be able to remotely pick up new appointments from your computer, get stock-trading alerts from your broker, or grab last-minute scheduling changes from the travel agent. Your digital camera might drop new pictures on your notebook or even send pictures directly to the photo processor for printing. Or...or... You can see what I mean about the allure of a future without wires.

The problem is that none of this is possible now. In fact, wireless networking stinks right now. The IT guys at our firm have to standardize on one vendor of wireless networking because it turns out that some cards don't work well with others. That's because the companies decided to add new features at the expense of real standardization. That's ludicrous, of course--a standard that can't be relied on isn't much of a standard.

It is also apparent that the mundane details of wireless networking render the dreams ridiculous. For instance, when I take my computer home, I have to start it up and tell it that we have gone home and it needs to use a different network. When I go to work the next morning, I have to reverse the process. Microsoft's new XP operating system will supposedly take care of that, but do I really want to get a whole new operating system for this purpose?

That brings me to the dream of public-access wireless. Someone has to install wireless access points in all those airports, hotels, coffee shops, and other public areas, and presumably that someone would like to make money doing so. The few hotels I've seen that let you connect to their wireless access points charge around $10. At Starbucks in many large cities you can pay something like 65 cents a minute or buy a monthly subscription. I have a subscription to get wireless access in any San Francisco-area Starbucks for $30 a month.

All this sounds okay, but think about it closely. My Starbucks subscription costs $360 a year. My firm isn't likely to pay hotels $10 a day too often--that might come to $1,000 a year for me, and when you add in the other partners, we're talking a big expense. In other words, even though I was thrilled when I first went into Starbucks and downloaded my e-mail at network speeds, the thrill alone is not worth the cost. (Besides, I think of Starbucks as a place to get away from my computer, not as a place to bring the damn thing!) In other words, the economics of wireless networking are all wrong now. Sure, the visions are pretty darn appealing. But the reality is such a bummer that those visions are going to get pushed back further and further. Let's hope they don't disappear.

STEWART ALSOP is a partner with New Enterprise Associates, a venture capital firm. Except as noted, neither he nor his partnership has a financial interest in the companies mentioned. He can be reached at alsop_infotech@fortunemail.com. His column may be bookmarked online at www.fortune.com/technology/alsop.