My club experience is pretty limited, as I just don't find the scene very fun, but I was very entertained by a party I attended a couple years ago, and it looks like they're throwing another one this weekend. Might be a bit freaky for you if you're into top 40, but it should be a pretty cool departure from Ottawa. Go to http://mother______nyc.com (fill in the blank--hint: rhymes with "plucker").

For more mainstream fare, when you arrive you should pick up a copy of Time Out NY magazine, available at pretty much any newsstand. They have a whole section devoted to clubs, including pretty extensive weekly listings. You won't necessarily find the "coolest" super-secret parties in there, but you can get an idea of the kinds of music and cover charges you can expect at various established places. And they'll probably have the motherf___ party listed in there, too.

Time Out also publishes an annual guidebook to NYC bars and clubs, so you might also want to stop by a bookstore and browse that, as it'll be more comprehensive (but less up-to-date) than the magazine.

Finally, here are some online resources:
http://www.timeout.com/newyork/section/clubs
http://www.clubplanet.com/