I don't know when NY is exactly, but I know its AFTER 11/1. South Carolina and Florida are around halloween, and I know the two of them are first in filing deadlines.
IOWA CAUCUS: No deadlines and no paperwork filed, no signatures collected. The Caucus is currently scheduled on February 6th, 2012. So Gov. Palin could declare candidacy on February 5th, 2012 and still be able to participate.
Some of the Filing Deadlines I could find...right now it looks like South Carolina is earliest deadline.
SOUTH CAROLINA: Nov 1, 2011
TEXAS: Dec 12, 2011
ALABAMA: Dec 14th, 2011
NEVADA: Mar 12, 2012
Some require signatures for example
PENNSYLVANIA: Feb 14th, 2012 filing deadline with 2000 signatures required
NEW YORK is currently set for an April 24th primary. I cannot find a filing deadline.