Google has launched its revamped Voice service, formed on the basis of its GrandCentral acquisition. At the moment it looks like it's mostly PC-based, and dovetails with Gmail.
Predictably, the world & his dog are putting two and two together (Voice + Android) and calling it the death knell for the operator as a "voice pipe" by using an mVoIP work-around.
For various reasons, this seems implausible in the short term - not least the low likelihood of any two people both having Android phones, with flatrate data, and HSUPA coverage, and sufficient battery power to run not both the OS but all the voice processing and so forth.
The other option is some sort of callthrough / callback option using circuit calls, perhaps subsidised by adverts. This might work in the US, but elsewhere in the world the interconnect fees to mobile numbers are prohibitively high.
Maybe Google's got some clever voice-recognition technology that could pick out words in phone conversations ("restaurant", "flight", "car", "gig"), which coupled with lax privacy rules could allow some clever advertising or other services, along the lines of Pudding Media's proposals from a year ago, or indeed, my own from three years past. Maybe that could subsidise termination fees at some point.
In any case, an Android / Google Voice pairing would probably make last week's hoo-ha about Nokia+Skype look comparatively trivial from an operator standpoint. Or at least it would if anyone actually gets around to developing desirable/capable Android phones.
But to me, [and this is total & utter random speculation on my part] the real deal would be if at some point Apple partnered with (or, better, acquired) Skype or BT/Ribbit or Truphone or someone like that. Then the cat would be well & truly among the pigeons.....