tracking strenght training

I use a Heart Rate Monitor that also calculates calories during my workouts. I use the Polar FT7 and got it for about 86 bucks via Amazon.com. The calories burned are fairly accurate, and are based on a few stats you enter on the watch and adjust accordingly (weight). I use this whenever I strength train or jog, walk to work, etc.

There's a "strength training" category under cardiovascular part of the exercise tab.

It does not calculate calories burned however. It is mainly for keeping track of what you have been doing and any progress you've made with sets/reps and weight used.