Equals' Party Line is a new, free voice conference app that lets you instantly connect with up to five of your friends in a voice conference. Unlike the business-focused Vello, , Party Line is limited and designed primarily to connect you with Facebook buddies. However, you can cram non-Facebook users into it and it could easily be used in work settings.
Once you set up your "party lines" and invite friends into them, kicking off the voice chat is a snap. You can either initiate the conference from the Facebook app, or just call the service from the phone you registered with it. On the Facebook app you can monitor the call to see who's joined and who hasn't. The other participants don't need to install the app for you to reach them, but if they do, they can also set their availability, including setting a do-not-disturb flag.
If you call in to Party Line to kick off a party line chat instead of doing so from the Facebook app, you get a simple prompt to select the line you want to connect with, and then Party Line will call everyone and place them into conference.
Party Line's limitations made setup a bit confusing, though. You can only have five friends per party line, and you can't shuffle them around as easily as I think you should be able to. And while you can add non-Facebook friends to a line, that's clearly not the focus of the service.
I tested the service on a mobile phone, which made it hard to judge voice quality. There was a lot of lag, though--more than just between two mobile phone users. That makes natural conversation awkward.
I still like Party Line, though. It's free (ad-supported), in contrast to other business-focused conferencing systems that call mobile phones, and it provides an almost Nextel-like immediate way to connect with a small team or group of friends.
Equals is a new company and will be releasing other communications apps shortly, including a "universal inbox" product to come in June.