When iOS 5 launches, Facetime calls over 3G will be possible. But according to 9to5mac's sources, Verizon only wants 3G Facetime available to users who have tiered data plans, not unlimited ones. Apple doesn't like this.
Apparently Apple wants 3G Facetime available to all iPhone users as part of a uniform experience. But Verizon is arguing against that to limit the flood of video traffic on their network. If users have limited bandwidth, they won't waste as much of it on Facetime, and Verizon worries less about their service faltering. This could also just be a ploy by Verizon to get people to move away from their unlimited plans when its time to upgrade their phones (though I wonder how many people will regularly use Facetime, even with 3G). But regardless, it seems the two companies can't agree to terms, and it could hold up the release of the feature when Apple makes it available this Fall. [9to5mac]