DOT Commissioner Janette Sadik-Khan and Deputy Mayor Howard Wolfson are appearing at a press conference this afternoon to announce the details of the city's semi-controversial bike share program, which will provide New Yorkers with 10,000 public bikes at about 600 stations. Nothing's been officially announced yet, but the radical bike lobbyists at Streetsblog hear that the Portland company Alta Bike Share has been chosen to run the program, which will reportedly cost New Yorkers under $100 a year. But if you use a bike for less than a half hour, it's free!

Streetsblog's source also says the city is refusing to subsidize the program, and that it must be financially self-sufficient. The equipment provider for Alta participated in a bike share program in Montreal which, according to the Times, needed a government bailout to the tune of $108 million. But the company also operates the Capital Bike Share in Washington, which has proven popular, and launched another bike share system in Boston earlier this year. Both of those networks are much smaller than what's expected in NYC, and some critics are concerned that the bike stations will put too much strain on overly-crowded sidewalks.

"DOT and Janette Sadik-Khan’s problem is they say, ‘Here’s what we’re doing, take it or leave it,' " Sean Sweeney of the Soho Alliance tells the Observer. “Instead, it should be, ‘Here’s 20 racks, where would you like them?" But the DOT has promised to work with the City Council to determine where the bike stations will go. According to Streetsblog, the service area will stretch from the Upper West Side and Upper East Side to Bed Stuy and Greenpoint. We'll have more details after the official announcement today; for now, here's a Streetsfilm segment on D.C. bike sharing in action:

The Phenomenal Success of Capital Bikeshare from Streetfilms on Vimeo.