I found this site -- http://nyc-safestreets.org/home.htm -- via The Village Voice tonight. The site aims to give women in the city information about sexual assaults that have happened in the neighborhoods where they live or hang out, as well as information about local businesses that are willing to act as "safe havens" for women who fear that they are in danger of assault.
The volunteers who have created the site live in Green Point, Williamsburg and Chelsea, so their current reach is fairly limited. The hope is that, with the attention they get from the Voice article, they'll get more volunteers and businesses involved and eventually map the whole city with safe havens.
Good luck. Be safe.