It looks like VoIP is really starting to go mainstream and while Apple plays footsie with the regulators, Google is coming out full bore embracing VoIP on the Android.
A quick read of the official Google blog says so. But other than SiPDroid and a Gizmo client attempt, nothing really is there yet that does the trick over WiFi.
The other thing is 3G. As noted earlier, 3G voice is good if you want to be standing still, but in motion, it leaves a lot to be desired. That's why in my view alot of this is part of the game of getting ready for LTE by saying..."look here. We're ready for you..."