New York is well supported by a variety of shared spaces, incubators and accelerators that can provide affordable office space and resources for ventures in a multitude of industry sectors. What is best for you depends on what business you are in and what kind of help you are seeking. The list of incubators, accelerators and co-working spaces has been constantly increasing. For an up-to-date list of co-working spaces, there are a number of sites one can consult, such as Mark Birch’s blog or the CoWorkingNewYorkCity wiki.
Some of these incubators and accelerators will help you in their own area of expertise. Some have a competitive admission process (e.g. Techstars) but offer some initial funding and exposure to mentors and investors.
New York State/New York City-associated
Tech Accelerator Programs
Health Care Accelerators
Digital Media/Technology Incubators