Reads an 8 bit value (0 - 254) from the analog to digital converter and moves two stepper motors to a relative position within the motor's range (0 - 63). You could also use the Arduino map() function to translate the different ranges.

stepper_position_pot.ino

#include <AccelStepper.h>
// Define a stepper and the pins it will use
//AccelStepper stepper; // Defaults to AccelStepper::FULL4WIRE (4 pins) on 2, 3, 4, 5
AccelStepper xAxis(1, 4, 3); // pin 3 = step, pin 6 = direction
AccelStepper yAxis(1, 6, 5); // pin 3 = step, pin 6 = direction

#define Xpin A0
#define Ypin A3

void setup()
{  
  // Change these to suit your stepper if you want
  xAxis.setMaxSpeed(30);
  yAxis.setMaxSpeed(30);
}
void loop()
{
  // Read new position
  int Xpos = analogRead(Xpin) /4;
  int Ypos = analogRead(Ypin) /4;
  xAxis.moveTo(Xpos);
  yAxis.moveTo(Ypos);
  yAxis.runSpeedToPosition();
  xAxis.runSpeedToPosition();
}