http://stackoverflow.com/q/9455376/326257

gistfile1.aw

<?php

$username="username"; 
$password="password"; 
$cookie="cookie.txt"; 
$url_login = "https://login.comcast.net/login";

// login

$ch = curl_init($url_login);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE); 
curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.6) Gecko/20070725 Firefox/2.0.0.6"); 
curl_setopt($ch, CURLOPT_TIMEOUT, 60); 
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, TRUE); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE); 
curl_setopt($ch, CURLOPT_COOKIEJAR, $cookie); 
curl_setopt($ch, CURLOPT_REFERER, $url_login); 
curl_setopt($ch, CURLOPT_POSTFIELDS, "user=".$username."&passwd=".$password."&rm=2&deviceAuthn=false&forceAuthn=true&s=ccentral-cima&r=comcast.net&continue=http://xfinity.comcast.net/&lang=en&submit=sign_in"); 
curl_setopt($ch, CURLOPT_POST, TRUE);
curl_exec($ch); 
curl_close($ch);

// get content

$ch = curl_init("http://xfinity.comcast.net/");
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE); 
curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.6) Gecko/20070725 Firefox/2.0.0.6"); 
curl_setopt($ch, CURLOPT_TIMEOUT, 60); 
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, TRUE); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE); 
curl_setopt($ch, CURLOPT_COOKIEFILE, $cookie); 
curl_setopt($ch, CURLOPT_REFERER, $url_login); 
$result = curl_exec($ch);
curl_close($ch);

// work with $result freely