Social networking site Facebook could soon get voice chat if trials of a new plug-in prove successful.

Virox, which has developed voice chat software for games and virtual worlds such as Second Life, is beta-testing a plug-in that lets users add a 'voice channel' to their Facebook page.

"It's a simple browser plug-in. You can invite as many friends as you want to the channel," says company spokeswoman Karen Blondell.

The free plug-in should be available in about three to four weeks, although the current beta test is closed to the general public, the company says.

This isn't a no-frills, one-to-one chat app either. "As big as your group is, you can hold conference calls, podcasts. You can have two people in a channel, or several," says Blondell.

Users will also be able to talk with people who don't use Facebook. Vivox will provide a phone number for non-users to call in and join the conversation. It's unclear at this time, however, if Vivox will charge for this dial-in feature.

The plug-in should prove popular to third-party Facebook application developers. For example: games with an integrated voice component would be a natural fit for the Vivox app. And retailers who've set up shop on Facebook could use the plug-in to chat with customers.

In many ways, the Vivox app sounds a lot like web conferencing software such as WebEx and GoToMeeting, albeit on a much simpler scale.

For instance, Facebook users will be able to hold broadcast-style conferences in which they speak to large groups. The Vivox app will include a mute switch to prevent the audience from disrupting the speaker's presentation.

The plug-in is for audio chat only, not video. While video could be added further down the line. "it's not the focus right now," Blondell says.

Broadband speed test

See also: Facebook passes 300 million users, makes money