Let's continue our discussion on the explosion of instant messaging and VoIP applications started with the launch of Google Talk and expanded by eBay’s recent acquisition of Skype.

If you've ever wanted to do a teleconference like the big boys, with four or five rooms full of people conversing over speakerphones and long distances, you have your wish. Even better, you can now do this essentially free (after you pay for the teleconferencing speakerphones).

First, you need a telephone service of some type that supports teleconferencing. Since "free" is the operative word, Skype comes to mind first. The standard Skype client, supports five connections on one phone call. You and four others can be in a teleconference, all free, as long as you all have a broadband connection.

Start the teleconference from a system with high bandwidth, because the initiator will carry the load by hosting the conference call. Believe it or not, even PDAs with Skype software can be part of a conference call, but they can't initiate the call; they must be invited after the call starts.

Of course, the typical headset used by Skype customers won't support a roomful of users. Those Skype fans who use microphones and computer speakers will be disappointed that Skype won't support a natural sounding teleconference, or even the odd conversation that passes for natural sounding conversation on a teleconference.

Enter the Duet USB Speakerphone from Phoenix Audio Technologies. This small silver unit, not much bigger than a fully stuffed billfold, promises "boardroom conference quality outside the boardroom" and provides some other goodies as well.

Installation? Plug the speakerphone’s USB cable into your computer, which pre-empts the speakers and routes all sounds through the Duet. I tried this on an old Pentium III laptop running Windows 2000, and it worked as advertised. I dialed up a Skype contact, invited another, and had a three-way conference with perfectly clear audio to and from.

This unit relies on the existence of a softphone, like Skype, Google Talk or any of the other VoIP services, to make and answer calls. There's no dial or other controls on the Duet except for mute and volume up and down. Using a "real" speaker lets the Duet support audio bandwidth of 20 Hz to 7.5 kHz compared to a regular telephones range of 300 Hz to 3.4 kHz and pass along the full glory of Skype calls. Since Google Talk uses the same sound engine as Skype, the quality matches, but Google says nothing about conference calls yet.

James Gaskin writes books (16 so far), articles and jokes about technology and real life from his home office in the Dallas area.