form.html:
<html>
<body>
<form action="submit.php" method="post">
<input type="text" name="email">
<input type="sumbit" value="Go">
</form>
</body>
</html>
submit.php:
<?php
// connect
$email = $_POST['email'];
$email = mysql_real_escape_string($email);
mysql_query("INSERT INTO emails (email) VALUES ('$email')";
?>
======================================================
look
me or you at the insert try:
VALUES ({'$email'})
or
VALUES ({$email})
or
VALUES ('{$email}')