The new Citi Bike racks are in just west of Madison Square Park as part of the massive new NYC bike sharing program. Now we just need the bikes. The program lets you grab a bike out of the rack and ride to your destination and then return it to another bike rack station. There will reportedly be 600 stations and 10,000 bikes in the system. Word is they will launch this month.
How does it work? You buy a pass for 1 day ($9.95), 7 days ($25), or a year ($95), and with that you can use any bike in the system, and return it to any docking station in the system (See plans at https://citibikenyc.com/pricing). The 1 and 7 day members get 30 minutes to use a bike per trip, and the annual members get 45 minutes per trip at no additional charge. So from what we understand, you can take as many trips as you want, but they each must be under 30 or 45 minutes depending on your membership. Buy your memberships at https://citibikenyc.com/signup.
You can even use an app that shows real-time bike availability at different stations.
Here is a map which shows where the proposed stations will be near Madison Square park and the Flatiron, and how many bikes it will hold (see the full map here):