New York City is set to announce a bike sharing program that will encompass much of Manhattan and Brooklyn by 2012, broadening the city's focus on facilitating bicycle transportation.

The proliferation of bicycle lanes winding through New York City has become a contentious issue for New Yorkers, who feel they are witnessing either the modernization or the destruction of their city. Two different respected New York weeklies have devoted their covers to the topic -- the Observer dubbed it the city's last culture war -- and Transportation Commissioner Janette Sadik-Kahn has become a polarizing public figure for her bicycle advocacy.

Mayor Michael Bloomberg announced on Wednesday that the city had selected Portland, Ore.-based Alta Bike Share to help implement a network of bicycle racks equipped with bikes for rent; 10,000 bicycles would be available at about 600 stations from south of 79th street in Manhattan to certain Brooklyn neighborhoods.

The whole point is it needs to be dense, a city official told The New York Observer. It needs to serve a lot of different trips in order to be viable.

Alta Bike Share was selected from a field of companies who submitted bids to run the program. The bidding process stipulated that the winning proposal would not cost any taxpayer money and that the firm running it would share any profits with the city.

The Department of Transportation recently responded to City Council members complaining that they were being excluded from the process by agreeing to hold hearings on the bike sharing program before it's operational.