Here is another free service (at least for now) It is called webhuddle at http://www.webhuddle.com I tried it out and it really works nicely and has built in voip. There is not an invitation feature that I could find (the only downside) And the security certificate has a typo that causes it to give a warning but you can see its just that the www. is missing on the certificate. I believe that Robin Good reviewed this one as well.