Skype VoIP service is total crap. Your better off getting a magik jack at least the quality of calls is good. see:

http://www.conferencecallspot.com/2008/08/skypecast -teleconference-servive.html

Skype is one of the best and the nost popular companies offering the free VoIP communication ability. With the service offered through Skype, you can make free calls anywhere across the globe. The free VoIP services offered uses software that you can download in a matter of minutes. Once downloaded, all you need to do is register and you are ready to start enjoying free services. To use their services there no need to make any configure changes to network infrastructure or firewall. A professional site and customer service, in addition to clear sound, makes this a legitimate winner for most.