This weeks carnival of the mobilists as well as picking up my post on rethinking the mobile device has a post from Martin Sauter on Wireless VoIP in which he outlines the various technologies on available for such services.
However he does not mention the service I picked up yesterday on Spain's trial of VoIP using Disk On Key technology. In trying to discover more on the Start-Up that has developed the technology I spoke with someone who said that I should also take a look at Tatara Systems. In doing so I discover that they have quitely been used in deployments by both O2 and Vodafone but the PR has been extremely poor or the Networks don't want too many people asking questions about lower call prices.
My To DO list now has yet more Companies to meet in trying to get the information needed to make a judgement.