One specialized local library you may want to visit is the Library of the General Society of Mechanics and Tradesmen. You must join in order to check out materials ($50 for an individual), though the collection (the Mechanics' Institute) that focuses on the building and construction trades is non-circulating (and open by appointment only). But check it out -- according to the library's catalog, you can borrow The Natural Plaster Book: Earth, Lime and Gypsum Plasters for Natural Homes (chapter 6: "Applying Earthen Plaster to Straw Bale Walls").

Another (or an additional) option is to request specific titles (such as the above-mentioned?) via Interlibrary Loan in your local public library. Search WorldCat or even Amazon to find titles that look useful to you, and even if they're not in any of the NYC public library systems, you may be able to get them through ILL. For example, if I do a simple keyword search for "natural building" in WorldCat, I come up with titles such as A House of Straw: A Natural Building Odyssey, which then leads me to the subject heading "Straw bale houses -- Design and construction," which then leads me to almost 70 other titles on just that topic. Some are videos and DVDs, which may be available via ILL at the New York Public Library (other library systems, such as Brooklyn PL, allow ILL on print items only).

ILL can take up to a few weeks to get your request(s) to your local branch, and some libraries will not lend out a particular item to another library system, but it's a great resource and always worth a try.

Of course, relevant articles might be found in some of the databases that your public library subscribes to.

As for workshops, upstate this summer there's a Natural Building Colloquium. The Natural Building Network site lists workshops all over the country, some in NY State.

Other resources:

Sustainable Building Library (Seattle)

Green/Sustainable Building (University of Illinois at Urbana-Champaign library guide)