One of the keys to success in any daily transactions fantasy baseball game is figuring out who the truly awful pitchers are, and using hitters who are playing against them. Taking advantage of these matchups isn't quite as easy as it sounds though, since not only do you have to identify the worst of the worth, and evaluate exactly how great the impact of their badness is, but most of them don't last long in the major leagues, and are quickly replaced by minor leagues and converted relievers, some of whom are decent pitchers and some who aren't any better. Also, in many cases, the worst statistics are put up by young pitchers who may improve, or pitchers suffering from injuries, whose health may improve over time. So you need to pay close attention to whether the best indicator statistics (K/9 and BB/9) are showing improvement.
That said, it's always good to go into the season knowing which pitchers to target. One of my favorites in 2009, assuming he's in the major leagues, is Gregory Reynolds. Not only was he really, really bad in 2008 (K/9: 2.9, BB/9: 3.4, GB%: 45.1%), but you get the added bonus that he pitches in Colorado! His strikeout rates in the minor leagues were also quite low, so really the only real hope for him to be any good is if he improves a lot AND it turns out that he was unlucky with his groundball rate in 2008 and that his true rate is above 50%.