Code Sample for Arduino C: (by Bruce Allen http://www.arduino.cc/playground/Main/MaxSonar)

//Feel free to use this code.
//Please be respectful by acknowledging the author in the code if you use or modify it.
//Author: Bruce Allen
//Date: 23/07/09

//Analog pin 1 for reading in the analog voltage from the MaxSonar device.
//This variable is a constant because the pin will not change throughout execution of this code.
const int anPin = 1;

//variables needed to store values
long anVolt, inches, cm;
int sum=0;//Create sum variable so it can be averaged
int avgrange=60;//Quantity of values to average (sample size)

void setup() {
//This opens up a serial connection to shoot the results back to the PC console
 Serial.begin(9600);

}
void loop() {
pinMode(anPin, INPUT);

//MaxSonar Analog reads are known to be very sensitive. See the Arduino forum for more information.
//A simple fix is to average out a sample of n readings to get a more consistant reading.\\
 //Even with averaging I still find it to be less accurate than the pw method.\\
 //This loop gets 60 reads and averages them

for(int i = 0; i < avgrange ; i++)
 {

  //Used to read in the analog voltage output that is being sent by the MaxSonar device.
   //Scale factor is (Vcc/512) per inch. A 5V supply yields ~9.8mV/in
   anVolt = analogRead(anPin);
   sum += anVolt;
   delay(10);

}  

inches = sum/avgrange;
 cm = inches * 2.54;
 Serial.print(inches);
 Serial.print("in, ");
 Serial.print(cm);
 Serial.print("cm");
 Serial.println();

//reset sample total
 sum = 0;

delay(500);

}