function twitterSetStatus($user,$pwd,$status) {
	if (!function_exists("curl_init")) die("twitterSetStatus needs CURL module, please install CURL on your php.");
	$ch = curl_init();

	// -------------------------------------------------------
	// get login form and parse it
	curl_setopt($ch, CURLOPT_URL, "https://mobile.twitter.com/session/new");
	curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
	curl_setopt($ch, CURLOPT_FAILONERROR, 1);
	curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
	curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
	curl_setopt($ch, CURLOPT_TIMEOUT, 5);
	curl_setopt($ch, CURLOPT_COOKIEJAR, "my_cookies.txt");
	curl_setopt($ch, CURLOPT_COOKIEFILE, "my_cookies.txt");
	curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (iPhone; U; CPU like Mac OS X; en) AppleWebKit/420+ (KHTML, like Gecko) Version/3.0 Mobile/1A543a Safari/419.3 ");
	$page = curl_exec($ch);
	$page = stristr($page, "<div class='signup-body'>");
	preg_match("/form action=\"(.*?)\"/", $page, $action);
	preg_match("/input name=\"authenticity_token\" type=\"hidden\" value=\"(.*?)\"/", $page, $authenticity_token);

	// -------------------------------------------------------
	// make login and get home page
	$strpost = "authenticity_token=".urlencode($authenticity_token[1])."&username=".urlencode($user)."&password=".urlencode($pwd);
	curl_setopt($ch, CURLOPT_URL, $action[1]);
	curl_setopt($ch, CURLOPT_POSTFIELDS, $strpost);
	$page = curl_exec($ch);
	// check if login was ok
	preg_match("/\<div class=\"warning\"\>(.*?)\<\/div\>/", $page, $warning);
	if (isset($warning[1])) return $warning[1];
	$page = stristr($page,"<div class='tweetbox'>");
	preg_match("/form action=\"(.*?)\"/", $page, $action);
	preg_match("/input name=\"authenticity_token\" type=\"hidden\" value=\"(.*?)\"/", $page, $authenticity_token);

	// -------------------------------------------------------
	// send status update
	$strpost = "authenticity_token=".urlencode($authenticity_token[1]);
	$tweet['display_coordinates']='';
	$tweet['in_reply_to_status_id']='';
	$tweet['lat']='';
	$tweet['long']='';
	$tweet['place_id']='';
	$tweet['text']=$status;
	$ar = array("authenticity_token" => $authenticity_token[1], "tweet"=>$tweet);
	$data = http_build_query($ar);
	curl_setopt($ch, CURLOPT_URL, $action[1]);
	curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
	$page = curl_exec($ch);

	return true;
}

http://www.barattalo.it/2010/09/09/how-to-change-twitter-status-with-php-and-curl-without-oauth/

Since the 31 of august 2010, twitter made its API more secure, stopping basic authentication calls.
So, if you used basic authentication you have to change your code and implement oAuth authentication model or you can follow this link and found a mini spider that does the work.

How to change Twitter's status with php and Curl without oAuth

curl, php, twitter

PHP