Just use a html form:
<?php
if ($submit) {
$sqlinsert = "INSERT INTO users (name,password,email) VALUES ('$name','$password','$email')";
$result = mysql_query($sqlinsert);
}
else { ?>
<form method=post action=<?php $PHP_SELF ?>>
<table>
<tr><td><b>Name:</b></td><td><input type="Text" name="name" value=""></td>
</tr>
<tr>
<td><b>Password:</b></td><td><input type="Text" name="password" value=""></td>
</tr>
<tr>
<td><b>E-Mail:</b></td><td><input type="Text" name="email" value=""></td>
<tr>
<td><input type="Submit" name="submit" value="Add User"></td>
</tr>
<?php
}
?>