This VOX for Skype release from VoxLib is what I was writing about here as the product demo which blew my head off back at Spring VON in San Jose. While there are undoubtedly some interesting things happening in the FMC space, SIP clients on multi-mode phones and Skype on WiFi handsets, during the intervening years it will take for all these developments to permeate over 2bn handsets, speech recognition is a practical, sensible and painless solution for harvesting the benefits of VoIP on 2G cellular (or fixed line, for that matter).
I guess one potential drawback for some users is the need to have Skype and VOX running on a PC somewhere in the world. But I also wonder if this limitation doesn't present Skype and VoxLib an opportunity to offer "hosted presence" for those who may need it from time to time. In other words, Skype could host an "image" of the user's client (the contact list is not centralized in any event) and the VOX for Skype service. Personally I could certainly envisage paying a small fee for the ability to switch to hosted presence on an ad hoc basis, say when away on a camping trip or driving in the car. Maybe this is a far-fetched idea - I would be interested in your feedback.