А где достать скрипт рассылки писем с вложенным файлом?

на пхп их полно. идешь по линкам с пхп.нет и ищёщь подходящий скрипт...
Ну или хавай это:

class Mail
{
var $sendto = array();
var $acc = array();
var $abcc = array();
var $aattach = array();
var $xheaders = array();
var $priorities = array( '1 (Highest)', '2 (High)', '3 (Normal)', '4 (Low)', '5 (Lowest)' );
var $charset = "windows-1251";
var $ctencoding = "8bit";
var $receipt = 0;

function Mail()
{
$this->autoCheck( true );
$this->boundary= "--" . md5( uniqid("myboundary") );
}

function autoCheck( $bool )
{
if( $bool )
$this->checkAddress = true;
else
$this->checkAddress = false;
}

function Subject( $subject )
{
$this->xheaders['Subject'] = strtr( $subject, "\r\n" , " " );
}

function From( $from )
{

if( ! is_string($from) ) {
echo "Class Mail: error, From is not a string";
exit;
}
$this->xheaders['From'] = $from;
}

function ReplyTo( $address )
{

if( ! is_string($address) )
return false;

$this->xheaders["Reply-To"] = $address;

}

function Receipt()
{
$this->receipt = 1;
}

function To( $to )
{

if( is_array( $to ) )
$this->sendto= $to;
else
$this->sendto[] = $to;

if( $this->checkAddress == true )
$this->CheckAdresses( $this->sendto );

}

function Cc( $cc )
{
if( is_array($cc) )
$this->acc= $cc;
else
$this->acc[]= $cc;

if( $this->checkAddress == true )
$this->CheckAdresses( $this->acc );

}

function Bcc( $bcc )
{
if( is_array($bcc) ) {
$this->abcc = $bcc;
} else {
$this->abcc[]= $bcc;
}

if( $this->checkAddress == true )
$this->CheckAdresses( $this->abcc );
}

function Body( $body, $charset="" )
{
$this->body = $body;

if( $charset != "" ) {
$this->charset = strtolower($charset);
if( $this->charset != "us-ascii" )
$this->ctencoding = "8bit";
}
}


function Organization( $org )
{
if( trim( $org != "" ) )
$this->xheaders['Organization'] = $org;
}

function Priority( $priority )
{
if( ! intval( $priority ) )
return false;

if( ! isset( $this->priorities[$priority-1]) )
return false;

$this->xheaders["X-Priority"] = $this->priorities[$priority-1];

return true;

}


function Attach( $filename, $filetype = "", $disposition = "inline" )
{
if( $filetype == "" )
$filetype = "application/x-unknown-content-type";

$this->aattach[] = $filename;
$this->actype[] = $filetype;
$this->adispo[] = $disposition;
}

function BuildMail()
{

$this->headers = "";

if( count($this->acc) > 0 )
$this->xheaders['CC'] = implode( ", ", $this->acc );

if( count($this->abcc) > 0 )
$this->xheaders['BCC'] = implode( ", ", $this->abcc );


if( $this->receipt ) {
if( isset($this->xheaders["Reply-To"] ) )
$this->xheaders["Disposition-Notification-To"] = $this->xheaders["Reply-To"];
else
$this->xheaders["Disposition-Notification-To"] = $this->xheaders['From'];
}

if( $this->charset != "" ) {
$this->xheaders["Mime-Version"] = "1.0";
$this->xheaders["Content-Type"] = "text/plain; charset=$this->charset";
$this->xheaders["Content-Transfer-Encoding"] = $this->ctencoding;
}

$this->xheaders["X-Mailer"] = "Php/libMailv1.3";

// include attached files
if( count( $this->aattach ) > 0 ) {
$this->_build_attachement();
} else {
$this->fullBody = $this->body;
}

reset($this->xheaders);
while( list( $hdr,$value ) = each( $this->xheaders ) ) {
if( $hdr != "Subject" )
$this->headers .= "$hdr: $value\n";
}


}

function Send()
{
$this->BuildMail();

$this->strTo = implode( ", ", $this->sendto );

$res = @mail( $this->strTo, $this->xheaders['Subject'], $this->fullBody, $this->headers );

}

function Get()
{
$this->BuildMail();
$mail = "To: " . $this->strTo . "\n";
$mail .= $this->headers . "\n";
$mail .= $this->fullBody;
return $mail;
}

function ValidEmail($address)
{
if( ereg( ".*<(.+)>", $address, $regs ) ) {
$address = $regs[1];
}
if(ereg( "^[^@ ]+@([a-zA-Z0-9\-]+\.)+([a-zA-Z0-9\-]{2}|net|com|gov|mil|org|edu|int)\$",$ad dress) )
return true;
else
return false;
}

function CheckAdresses( $aad )
{
for($i=0;$i< count( $aad); $i++ ) {
if( ! $this->ValidEmail( $aad[$i]) ) {
echo "Class Mail, method Mail : invalid address $aad[$i]";
exit;
}
}
}


function _build_attachement()
{

$this->xheaders["Content-Type"] = "multipart/mixed;\n boundary=\"$this->boundary\"";

$this->fullBody = "This is a multi-part message in MIME format.\n--$this->boundary\n";
$this->fullBody .= "Content-Type: text/plain; charset=$this->charset\nContent-Transfer-Encoding: $this->ctencoding\n\n" . $this->body ."\n";

$sep= chr(13) . chr(10);

$ata= array();
$k=0;

for( $i=0; $i < count( $this->aattach); $i++ ) {

$filename = $this->aattach[$i];
$basename = basename($filename);
$ctype = $this->actype[$i]; // content-type
$disposition = $this->adispo[$i];

if( ! file_exists( $filename) ) {
echo "Class Mail, method attach : file $filename can't be found"; exit;
}
$subhdr= "--$this->boundary\nContent-type: $ctype;\n name=\"$basename\"\nContent-Transfer-Encoding: base64\nContent-Disposition: $disposition;\n filename=\"$basename\"\n";
$ata[$k++] = $subhdr;
// non encoded line length
$linesz= filesize( $filename)+1;
$fp= fopen( $filename, 'r' );
$ata[$k++] = chunk_split(base64_encode(fread( $fp, $linesz)));
fclose($fp);
}
$this->fullBody .= implode($sep, $ata);
}


}

юзается так:

$m= new Mail;
$m->From( "a@b.com" );
$m->To( "b@a.com" );
$m->Subject( "test" );
$m->Body( "Subj" );
$m->Priority(1) ;
$m->Attach( "/tmp/myfile", "multipart/mixed", "attachment" ) ;
$m->Send();

что-то кодировочка у тебя нестандартная