Any classes you know if to identify mid-century modern furniture in NY area?  

You're not going to find any...
You're not going to find any classes or seminars.
Best thing to do is buy books and visit mid-century shops.

additional knowledge possible
furnituregirl,
Other than reading books (an excellent idea) I would suggest multiple visits to MoMA and "kicking around" SOHO.
This may not help, but it certainly will not hurt.
http://www.moma.org/collection/browse_results.php?criteria=O%3ADE%3AI%3A1|G%3AHI%3AE%3A1&page_number=1&template_id=6&sort_order=2

Check this forum every day...
Check this forum every day and search through the thread archives if you're looking for info on any particular piece/designer. There may be a lot of gibberish you will have to sift through, but a significant portion of my knowledge of mid century pieces has come from DA, including about 95% of the Eames stuff.
You'll soon discover the posters worth paying attention to (certainly not including myself in that group).

Spend some time online
Definitely here on designaddict. Also worthwhile to look at past auction catalogs from Wright20 and the decopedia on deconet. I guess one of the things I really like about Wright20 is they usually provide pictures of any stamps/marks.
Not sure if anyone here has any strong opinions about the legitimacy or comprehensiveness of either source, but i'd be interested to find out.

It's very impressive what...
It's very impressive what Richard Wright has built in a fairly short time here in Chicago. While I don't know him personally, I believe he worked at Toomey in nearby Oak Park before starting on his own. The network of buyers and sellers that he had assembled over the years for high-end pieces is second-to-none between the coasts.
I look forward to each of the auctions in the same way I would a rotating exhibit at a museum, except you are able to touch and sit in the pieces at Wright. Indeed, high on my list when I visit next weekend is this Kagan stunner that rarely surfaces. . .