reading multiple char

hello to all~

i need some help in the following program:

int x; // integer x decalaraion
char p, *l; // declaration for charecter p and pointer to charecter l

void setup()
{
Serial.begin(115200); // begin serial communication
Serial.println("TEsT"); // debug string

}

void loop() //begin main loop
{
if(Serial.available()>0) //check if there is charecter in the serial buffer
{
p=Serial.read(); // read the serial data which is character store it in p
*l=p; // store address of character value p in char pointer l
x=atoi(l); // integer x equals ascii to integer converted l

delay(500);

Serial.println(x);
}
}

the program above only reads an int but i want it to read values such as 123.
i would really appreciate if someone could help me improve this program.

Some servo test code that might be of interest.

// zoomkat 10-4-10 serial servo test
// type servo position 0 to 180 in serial monitor
// for writeMicroseconds, use a value like 1500
// for IDE 0019 and later
// Powering a servo from the arduino usually DOES NOT WORK.

String readString;
#include <Servo.h> 
Servo myservo;  // create servo object to control a servo 

void setup() {
  Serial.begin(9600);
  myservo.writeMicroseconds(2000); //set initial servo position if desired
  myservo.attach(7);  //the pin for the servo control 
  Serial.println("servo-test-21"); // so I can keep track of what is loaded
}

void loop() {

  while (Serial.available()) {
    delay(1);  
    if (Serial.available() >0) {
      char c = Serial.read();  //gets one byte from serial buffer
      readString += c; //makes the string readString
    } 
  }

  if (readString.length() >0) {
    Serial.println(readString);  //so you can see the captured string 
    int n;
    char carray[6]; //converting string to number
    readString.toCharArray(carray, sizeof(carray));
    n = atoi(carray); 
    myservo.writeMicroseconds(n); // for microseconds
    //myservo.write(n); //for degees 0-180
    readString="";
  } 
}

Thanks Zoomkat!

yes the program is very helpful. I really appreciate your help.
Thanks again~