I'm in Boston today so couldn't make it to the totally non-secret 3/Skype launch announcement today.
As far as I can see, this is technically very similar to the earlier deal with Skype on the X-series products about 10 months ago. In other words, a software client on the phone acts as a 'dialler' for Skype, but doesn't actually use VoIP over the radio network. It uses a circuit call into a Skype gateway in 3's network. The earlier X-series one used iSkoot on the Symbian platform - whereas this one has an application built-in to Qualcomm's BREW framework.
I'm expecting quite a lot of this type of hybrid 'dial through' option before we move towards 'proper' mobile VoIP over the next 2-3 years. It's a lot easier to guarantee decent QoS using this approach in the short term - especially as this deal is on a cheap phone which I expect uses a basic WCDMA 3G chipset. 'Ordinary' 3G doesn't support VoIP very well - there's too much latency and things like header compression are absent.
I'm expecting operator-led VoIPo3G (probably with partners like Skype) to start to become more important from the point at which full HSPA-capable (HSDPA+HSUPA) devices become common. This is already realistic for laptop modems, and will start filtering into more high-end phones in 2008
Yes, I was right about my guesses on this - just got conformation from the 3 PR folk. It's a low-cost WCDMA-only phone based on a relatively low-end Qualcomm 6245 'value platform' chipset.