More on GigaBeam
Stealth Communications, an NYC internet gateway and VoIP service provider, will use GigaBeam’s wireless GigE technology.
Light Reading coverage on this topic: GigaBeam, Stealth Expand VOIP Services
Om Malik writes about it: Stealth, GigaBeam team on VoIP
It appears the primary reason for choosing GigaBeam is the advantage of bypassing local infrastructure and its significantly lower levels of network access latency (expected to reduce by as much as 30% with this network).
I last mentioned GigaBeam here: GigE Network in the air over Manhattan