Are protein shakes appropriate for me?

Hello, this topic isn't addressed in the FAQ directly so thought I'd check to see if any fitness / nutrition gurus could help me out with this question . . .

I am working on gaining strength and muscle as well as losing fat. I'm currently about 5,10" 206 lbs. I carry most of my fat in my midsection.

I've been lifting weights for a while (a few months steady) and have finally developed a routine to work out at least 3 times a week.

I'm supplementing weight training with Cardio (treadmill, biking, racquetball) as much as possible in-between.

My question is: After my weight lifting sessions, is it a good idea for me to have a protein shake?

I like the fact that it can help me recover from the workouts and build muscle, but I'm worried about the extra calories that may hurt my plan to lose fat.

Anyone have any advice on this topic, or any others that can help me achieve my goals?

Thanks!