Have you tried Google St View?
Any more detail would be helpful. When you say down, you mean heading south, right? (amazing how many people get that confused)
Was the place on the southbound side or across the street.
Unless it is a new place you should be able to notice it (Google claims most of their St Views are < 1 yr old - unfortunately no way to get a precise date for any given area).
Could it be Horsefeathers? They seem to be more of burger, pub joint, but the review here mentions BBQ: http://www.yelp.com/biz/horsefeathers-tarrytown?rpp=40&sort_by=relevance_desc&start=40
post edited by WarmBeer - 2011/07/20 11:05:51