the city they enter is stored in a session variable called 'eCartCheckoutForm_shipping_city'
create a new city tax and set the trigger to Session Variable exists "eCartCheckoutForm_shipping_city"
AND
based on session variable value:
if the session variable "eCartCheckoutForm_shipping_city" has a value equal to "NY NY"
OR
based on session variable value:
if the session variable "eCartCheckoutForm_shipping_city" has a value equal to "Queens"
and continue adding OR statements for all of the NY Cites the tax should apply to.