In January of 2009 we learned that Comcast was engaged in a trial to offer free Wi-Fi service in and around the NYC commuter region, piggybacking in on Cablevision's Wi-Fi hardware mounts. In March of last year Comcast began pushing Wi-Fi throughout New Jersey, though the service was still technically a trial.

Today they've dropped us a line to note they're officially launching the service (named "Xfinity WiFi") across Northern New Jersey, "key beach towns along the Jersey shore" and the Philadelphia Metro area at no additional cost to Comcast residential broadband customers.

2,000 hotspots have gone live at this time (a location map is here), and all can be accessed with your existing Comcast username and password. Comcast is of course following in the heels of Cablevision, which has deployed service around the NYC commute area in order to help offer an additional perk in their competitive fight against Verizon FiOS. However, Comcast tells us that unlike around NYC, this is not a shared deployment with Cablevision.

This deployment appears to be Northeast only -- for now. "We plan to increase the number of spots in this area before the end of the year, but do not have plans to launch WiFi in other markets or nationally at this time," says Comcast.