High torque servo/stepper setup
The Dynamixel servos are quite popular for their precision, high torque, and nice controls. Unfortunately, you'll be paying for all those features. I recommend Trossen Robotics: Dynamixel servos
Trossen also sells a full pan/tilt setup for the Dynamixel servos: Trossen Robotics pan/tilt
They have a whole range of sizes and torques. ServoCity.com also sells some pan/tilt setups: ServoCity pan/tilt
Trossen provides a nice controller and software. I believe Pololu.com also sells servo controllers with information.
Servos will be much easier to interface with, while a stepper motor will provide greater angular resolution. How precise does your pointing need to be? The nicer Dynamixel servos will do steps of 0.3 degrees, while a stepper motor will get you much smaller incremets if you do the "micro stepping" method. Try looking at Sparkfun for a stepper/stepper driver: Sparkfun.com


PS. When you're done with your project, how about adding it to RobotBox :)