See http://www.ontarioabandonedplaces.com/searchmont/searchmont.asp for full description.
There are no trespassing signs up at the entrance, but the kids in Searchmont don`t seem to care. The last couple times I`ve gone there, kids were dirt biking outside or skateboarding inside the buildings. A friend of mine did get kicked out by one of the locals while taking picutres in there, though.
There`s lots to see here. The factory itself is quite large and has some old equipment in it. There is an old cemetery outside, as well as an abandoned church out front. They filmed an episode of Mantracker near here, in which the Mantracker spent the night in the factory. It`s a very eerie place.
Update: Factory is currently being demolished as of April, 2014. I'm told the church is being left intact, though.