There is a lot to this and more than meets the eye with this move by Verisign. Any of the companies already aligned with them in the VoIP or WiFi handoff space are in for a very long ride. While some aspects may be bumpy at first, there is a lot of need for the handoff between a WiFi network and a traditional cellular network.
The companies in that space who have the intellectual property and the ability to deploy it from core of the network out to the end points and all the links of the wireless and wireless chain in between will be the winners, IMHO.