Another way is to keep tabs on the internet, but if you want "real-time" changes of what's coming on the market in the building, I would contact a competent Realtor.
If you are looking to move across the country let me know, I work with buyers in lots of downtown areas, including the Village.
If you are simply shopping for a second home be aware that that co-op board does not allow pied-Ã -terres, and you should look elsewhere.
author, "Diary of a Real Estate Rookie"
Insider Real Estate Tips with a Twist of Humor: http://tinyurl.com/2ag28z
ali [at] dgneary [dot] com