Now let it be told, New York City residents can find out street parking regulations by clicking on the New York DOT online parking sign map.
If you go to the map and click on the parking sign, you can see, in plain text form, what the rules are for that block.
The map also shows DOT's street condition assessments -- most are "good" -- as well as surfacing information.
On my browser, the map had an annoying habit of blowing up any time I requested information, but so far as I could tell, the info seems to be accurate.
And of course, it doesn't tell you where you'll find a spot. For that, try roadify.com.