Just completed a PCB design for driving one leg of the BuckBot uses a PCA9533 LED Driver to provide four PWM signals to (up to) four servos on each articulated leg.

  Boards on the way from OSHPark.  The LED Driver talks to a PIC microcontoller over the I2C bus.  Servo positions are, therefore updated digitally.  A single sequence of 8-bit words moves the whole leg through its paces.  Link to view the pdf is:  http://www.ranarchy.org/SERVO_BOARD.html