From the March 2004 issue of Entrepreneur

As more phone traffic travels over the Internet, more computers will be doubling as telephones. Any Internet-connected desktop, laptop, tablet or PDA with a mic and speakers can become a softphone by adding a small inbox/dialer client that links to an Internet-connected server elsewhere.

Why bother? Because calls traveling exclusively over the Internet cost the same whether the other party is across the street, across the country or around the world- and that cost is usually zip, zero, nada.

Another reason is that, technically, the Public Switched Telephone Network (PSTN) and even cellular networks don't actually route calls to you personally; they call a handset. IP phone systems do a much better job of tracking you down wherever you may roam-and these days, more of us spend more time out of the office than ever before.

There are lots of ways to add phone capability to a computer. None of them are free, but all are money savers. VoIP services like Dialpad Communications (www.dialpad.com), Net2Phone (www.net2phone.com) and Vonage (www.vonage.com) let you download their softphone inbox/dialers to your computer for free, as long as you use their discount VoIP services.

If you already have an IP server at the office, it probably has a mobile computer option, too. Avaya's IP Softphone extends all the rich telephony services of Avaya's (www.avaya.com) office phone system to any Windows-compatible portable for a one-time licensing fee of $130 per user. That includes a Pocket PC connected to the Internet over a Wi-Fi hot spot.

In fact, softphone-specific ventures like TeleSym (www.telesym.com) and Media-Streams USA (www.media-streamsusa.com) believe the growing archipelago of public and private Wi-Fi networks is going to provide a new era of last-mile IP phone connectivity for mobile workers. Like other inbox/dialers, TeleSym's SymPhone and Media-Streams USA's e-phone rely on full-featured servers back at the office, where all the necessary telephone-style switching and directory services are handled. After a one-time, per-user payment of about $200 to $250 or more (depending on the volume ordered) for SymPhone and $480 to $690 for e-phone (depending on how many licenses are purchased), staffers can make unlimited free Internet calls, probably saving that much in long distance in a couple of months.

They'll also get more calling and voice-mail flexibility. Softphone clients let you merge or share information with other inboxes-including Microsoft Outlook in the case of SymPhone and e-phone-capturing caller-ID information in phone books and making outgoing calls by clicking a contact entry. Voice-mail messages can be stored on your computer as .wav files and forwarded as e-mail attachments.

IP telephony will really get mobile this fall, says Mike Houston, senior product marketing manager for Bellevue, Washington-based TeleSym. By then, equipment and agreements should be in place to let calls travel between 802.11x and cellular networks as necessary.