Get rid of Clemens immediately! Trade him for as high a draft pick as you can get and a top flight pitching prospect like Edwin Jackson for instance(the Dodgers will trade Ishii).
Also try to get some sort of value for Maddux, the last thing you need now are aging pitchers, or even hitters. Your looking at 2006 at least to be competitive, probably longer.
Keep Blalock,Rollins,Kent and Rivera, but also keep Pena and Shawn Green or even better Jack Wilson. You could trade Wilson in May or June as he will continue to tear up the NL and someone will love to give up some young gun or arm to acquire him. Also always try to stockpile draft picks for next winter.
Make sure you don't flat turn down any trades, counter,or politley decline with an eye to the future, if someone offers you a player, make a note somewhere of the player that was shopped for future considerations. And consider trades with 2006 and beyond in mind, of the prospects you'll acquire this year you'll be lucky if half turn out the way you think in the next few years.
Good luck, it will be an exciting season for you.