The limiting factor with deploying traditional wireless access points for street wireless access points has been the cost of tying those APs back into your network -- the back-haul. Normally this is done with a DSL or leased-line, which means a monthly recurring charge (and potentially an AP that can offer wireless at 11 Mbps, but only has a 1 Mbps feed).
Nortel's Wireless Mesh Network (WMN) gets around this by employing both IEEE 802.11a and 802.11b radios. The units are made to be hung from a light pole. They have two wires coming out of them for AC power -- and that's it. Protruding from the bottom of the hexagonal AP are two whip antennas. These provide 802.11b wireless connectivity for users on the street below. The six side panels of the AP are 802.11a antennas. The WMN APs use their 802.11a radios to connect to each other. They run a traffic routing algorithm that's OSPF-like to determine best paths through the network of APs. You provide a hard-wired Ethernet connection to one or more of the APs and now the WMN has a path to the greater network. The result is a mesh of APs cooperating with each other to carry user traffic, with a minimum number of back-hauls.
In Hartford this means that I could deploy WMN APs along Main St. and in the vicinity of Adrian's Landing (Columbus Blvd), give the APs at Hartford Public Library, and our offices Ethernet connections, and provide free 'net access. HPL and our offices are already on our network, so there wouldn't be any monthly circuit costs. The APs themselves take care of getting traffic to and from the APs in between the APs with hard-wired connections.
WMN AP on the roof of the Media Lab
AP on the roof of an adjoining building
Distant AP; coverage extends into the Mariott