Si hai ragione...

Codice PHP:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml">    <head>        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />        </head>    <body>
<form action="http://theceasar.com/prova2.php" method= "POST">    Il tuo nome <input type="text" name="nome" value="">
     <input type="submit" value="invia"><br />
</form>
</body>
</html> 

Codice PHP:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml">    <head>        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />        </head>    <body>
<?php
$nome = $_POST['nome'] ;
echo "ciao ".$nome ;

?>

</body>
</html>