[RESOLVED] Replace string from database

[dclamp]

i make this function to replace strings in a text, from a database:

function form_filter($text) {
    $sql = "SELECT * FROM `form_filter`";
    $query = mysql_query($sql);
    while($a = mysql_fetch_array($query)) {
        $new = str_replace($a['replace'], $a['with'], $text);
    }
    return $new;
} 

and it doesnt work. can some one help?