I am trying to use my larger muscles more when I swing and I thought perhaps you had some type of specific drill with a medicine ball or some weight that would help develop my rotational strength.

Check out this post I made on Resistance Training for Batspeed.  The article in there covers a lot of basics about general, special and specific training for bat speed.  Each of the protocols referenced there were used successfully with high school and college athletes.

The medicine ball exercises are basically standing rotation movements similar to a swing – just pick a couple basics, there’s not one magic one..  You can look for more exercises here (specifically abdominal and plyometric drills) and also refer to the recent post on texas rangers s&c exercises.  It’s a good idea to mix in some of the bridge exercises for stabilization, and if you’ve been swinging and working out already you are probably okay to move in to the other med ball stuff. 

Also add some weighted implement training to your hitting routine.  This is what is going to take your developing strength and transfer it into your actual swing.  If you’re still playing at this point (in-season) just mix it in on the tee or soft toss.  For more ideas for the off-season, see this post on off-season training.

I recommend that you go over these things with your local baseball coach and/or strength and conditioning coach.  Good luck!

I’ve also been playing some catch up as far as reading up on different internet resources and a number of different books that I’ve ordered.  Here are a couple of nice links that you should find useful:

SB Coaches College is a site created by three well known coaches in the S&C industry and it has tons of articles and other information.  For example, here is a quick piece on a college softball dynamic warm-up program.

The S&C staff at the College of Holy Cross has assembled a video library of exercises that they use in their program.   Here are a couple that I like/use – 1-leg straight-leg deadlift (hip dominant hamstring) and cable lift rotation (although I’d make a point for the spine angle to stay vertical or slightly back as in the swing)…