The voter registration in NY State is today. If you haven't registered yet, the AP explains, "Only completed voter registration forms postmarked by midnight and received no later than October 15th will be valid for the upcoming general election." Additionally, if you've moved to a new county you need to reregister from your new address (and if you've moved within the county, you don't need to reregister by you should update your address with the board of elections). Here's the state Board of Elections website, the NYC Board of Election website, and the postal service's website so you can look up post offices. Additionally, the NJ deadline is October 14 (state Division of Elections website; more info) and Connecticut's is October 28 (state Secretary of State website).