Nice list of free pc to pc voip applications posted in July 2006 for those who are just starting to checking out alternatives to POTS (plain old telephone service) or who just plain forgot about somet of these at http://lists.econsultant.com/top-10-pc-to-pc-voip-services.html.
Skype, GoogleTalk, Gizmo Project, Ekiga, Yahoo IM, Windows Live IM, ICQ, Netmeeting, tglo, Babble (UK)... plus more ... BuddyTalk (remember BuddyPhone in the late 90's?), ineen, NetEasyPhone... are on the list, but I think you and I would like to add a few more such as ZoiPPE...
Uh, sorry, I have to get offline to go work out at the 24/7 gym and dig into paperwork at the Super Technologies, Inc. office in Pensacola, FL. Share the news of others with your friends and in comments here or on my Plaxo Pulse, Facebook, or Linkedin areas.
... browse some of our team's other blogs at http://blogs.didx.net and http://blog.tmcnet.com/monetizing-ip-communications/. You're welcome to comment, contribute, and collaborate any time.