In honor of the day I want to cook corned-beef in our slow-cooker. I've read several recipes that say to cook a 3-4 pound brisket for 9-10 hours. However, the corned-beef I bought is only 2 pounds. Should I still cook it for 10 hours? 
Yes, you should. The long cooking time breaks down the connective tissue in the meat, making it tender. It will take less time to get a two pound brisket up to temperature than a four pound, but we aren't talking hours difference, and longer is definitely better. 