There is a nice PHP class for the retrieving the data from Google Adsense account like impressions, clicks, ctr, ecpm and earnings - PHP account adsense monitor. But it does not work now, seems Google updated the authorization system for Adsense. I’ve fixed it a bit and now you can use it in your web applications.

A small example:

<?php
include('adsense.php');

$adsense = new AdSense();
if ($adsense->connect('username', 'password'))
{
  $data = $adsense->yesterday();
  var_dump($data);
}
else
{
  die('Could not login to AdSense account!');
}
?>

This code will output something like this:

array(5) {
  ["impressions"]=>
  string(2) "49"
  ["clicks"]=>
  string(1) "0"
  ["ctr"]=>
  string(5) "0.00%"
  ["ecpm"]=>
  string(5) "$0.00"
  ["earnings"]=>
  string(5) "$0.00"
}

You can download the script here.