Hi,

There are a few classes lurking around the internets to interface the twitter api with php. Google is your friend.

for those wanting some thing quick and dirty I threw this function together, which will post a message to your Twitter timeline.

WARNING; Theres absolutely no sanity checking going on here at all. Use at your own risk.

Code:
function updateStatus($user, $password, $message)
{
  $url = "https://twitter.com/statuses/update.xml";
  $curl = curl_init($url);
  $data = array('status'=>$message);
  curl_setopt($curl, CURLOPT_USERPWD, $user.':'.$password);
  curl_setopt($curl, CURLOPT_POST, 1);
  curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
  curl_setopt($curl, CURLOPT_HTTPHEADER, array('Expect:'));
  $result = curl_exec($curl);
}