435-855-3326
909-661-1234
712-858-9229
775-533-3500
985-425-2617
All of the above numbers are 100% free and all you pay is long distance. If you have free long distance on your cell phone (or home phone for that matter, like vonage or whatever) then you just use up your free minutes. If you have free nights and weekends, well, then it's completely free! Obviously nights and weekends are the busiest times for these and they can be busy sometimes.
Also there's a bunch at http://www.talkee.com although not all of them work or have people on them. Some of them are pay as well, but you will know when they are as they say if they are. Plus the number will be 900 or 976 or will require a credit card.
For most of these (all but the 909 one) you press 7 to accept the terms first. The talkee ones and a couple have their live rooms as option 1, then you select 1 through 9 for the rooms. Others have their live rooms on option 2, then it asks you upstairs or downstairs, 1 or 2, then you choose 1 through 9. Once you're in a room you can move up a room with 7, back a room with 6. There's also codes to let you get a private room with someone, etc. The system will tell you about it or talkee has a system map as well. The 909 one doesn't have a thing to accept, it just advertises pay numbers then takes you right into the first room. You hit # to change rooms 1-5.