I don't live in NYC but Craigslist can be a good option for finding a roommate.
I was looking for roomshares near my client-site and found one that said
"Room for rent. On suite bath. I am a consultant for XXX firm. I am XX years old. I ask that you be around the same age and a professional."
Well I fit the description so I met the guy in a public area, we hit it off, have been roommates for two years now with no issues. The sad (or good, depending on how you look at it) part is is that we are now each others closest friends.
If you are young you have the benefit that are many non-creepy people in your exact situation.