(FORTUNE Magazine) – There is an emergency halfway across the country, and you need to be there. Now. On your way to the airport, you dial the 800 number of an airline, any airline, trying to get a last-minute ticket to Chicago. Of course, the call isn't free, since you're on a cell phone. As you sit there stewing in traffic while the reservations agent puts you on hold to "check the computer," you wonder what's rising faster--your blood pressure or your cellular phone bill.

That's how John Clark, founder of Toll Free Cellular, got the idea for his Seattle-based company: stuck in a traffic jam. As its name suggests, Toll Free Cellular provides toll-free service on cellular phones. The service works just like regular toll-free numbers, except that you dial #-800 instead of 1-800 or 1-888. About 1,100 companies, ranging from Godfather's Pizza to Hilton Hotels, have Toll Free Cellular numbers. As of now the service is available only in scattered markets such as Seattle, Dallas, and Atlanta, but by the end of next year, cell customers all over the U.S. will have access to toll-free calls.

If truth be told, Clark was hardly the first person to get this idea. In fact, a handful of toll-free cellular services launched by carriers like BellSouth have come and gone in recent years. The problem has always been that the Federal Communications Commission's antitrust rules prevent cellular carriers from working together to provide toll-free service. For example, if Sprint set up a toll-free cellular service, the only people who could make free cell calls would be Sprint subscribers; all non-Sprint customers dialing those numbers would have to pay. Toll Free Cellular's third-party status exempts it from the FCC restrictions. So when someone calls a #-800 number, Toll Free Cellular gets a cut of the standard local per minute rate on every call in addition to its clients' monthly service fee. The carriers get the rest of the local per minute rate--and a new revenue stream that they can't capture on their own.

Toll Free Cellular has some impressive money behind it: $8 million in seed financing from a handful of west Coast venture capital firms, and another $14 million that came in from Goldman Sachs last autumn. (With that kind of backing, don't be surprised if the company does an initial public offering before long.) Goldman's enthusiasm is understandable--there is a huge demand for toll-free service. AT&T estimates that about 40% of its long-distance noncellular calls are toll-free; if Toll Free Cellular grabs even half that ratio of total cell calls, it could generate $2 billion a year in revenue.

Before it gets that big, of course, there are a few obstacles this tiny company (62 employees) has to surmount. First, it has to popularize its exclusive #-800 prefix until everyone knows #-800 is the cellular equivalent of 1-800. Another challenge is to seamlessly knit its service together across several different carriers spread all over the nation. (CEO Mark Lazar says the company has cut deals with several major carriers, including AT&T Wireless, GTE Wireless, and Southwestern Bell.) And while Toll Free Cellular has no competitors at the moment, its executives aren't fools. "We know that this is a tremendous opportunity and that it's only a matter of time before someone else enters the field," says Clark. When that happens, Clark may need another traffic jam epiphany.

--Ed Brown