This high-torque standard servo now comes in a metal-gear flavor, for extra-high torque (10 kg*cm!) and reliability! It can rotate at least 120 degrees (60 in each direction) with a classic 1.5-2.5ms pulse, but if you can extend your pulses it can go up to about 170 degrees - it varies a bit servo-to-servo. You can use any servo code, hardware or library to control these servos. Good for beginners who want to make stuff move without building a motor controller with feedback & gear box. Comes with a bunch of plastic horns, as shown. We now carry the Tower-Pro MG-995, they are very nice, high quality servos, excellent for use in robotics.
To control with an Arduino, we suggest connecting the orange control wire to pin 9 or 10 and using the Servo library included with the Arduino IDE (see here for an example sketch). Position "0" (1.5ms pulse) is middle, "90" (~2ms pulse) is all the way to the right, "-90" (~1ms pulse) is all the way to the left.