You could write your own functions/classes that connects to the server and issues the commands.
This would connect to the server and retrieve a list of messages.
<?php
function isok($string)
{
if (preg_match("/^+OK/", $string))
return 1;
else
return 0;
}
$stream = fsockopen("mail.domain.tld", 110, $error, $errorno);
if (!$stream)
{
echo "Couldn't connect: $error ($errorno).";
}
else
{
$buffer = fread($stream, 1024);
if (!isok($buffer))
echo "Error: $buffer";
fwrite($stream, "USER username"

;
$buffer = fread($stream, 1024);
if (!isok($buffer))
echo "Error: $buffer";
fwrite($stream, "PASS password"

;
$buffer = fread($stream, 1024);
if (!isok($buffer))
echo "Unable to login.";
else
{
fwrite($stream, "LIST"

;
$buffer = fread($stream, 1024);
preg_match("/^+OK ([0-9]+) messages/i", $buffer, $matches);
echo "You have " . $matches[1] . " new messages.";
}
fwrite($stream, "QUIT"

;
fclose($stream);
} //Daniel