i don't have first hand experience with cutting weight but i've heard nothing but great reviews about Animal Cuts by Universal Nutrition:
http://www.bodybuilding.com/store/univ/cutsfree.html
But supplements should always take a backseat to healthy dieting and spreading out your meals throughout the day. To keep fat down, I drink a lot of green tea because that boost thermogenesis (essentially fat burning) so the weight I gain is only the weight I want to gain