accurate geocoders for New York City

I am using geocoder.us to get the LL info for New York City addresses.
Snice I know the locations, I can tell that it is off target in many
spots. Sometimes it give coordinates for the wrong side of street/ave.
In many cases, it is a a block or two off.

Is there a better techniqueto accurately convert NYC addresses to
longitude and latitude coordinates that Google maps requires? I am
currently doing it manually, so I don't need an automated service.

Needs to be free, natch.

Any advice?