per la prima parte...

<html><head>
<title> Lista di selezione </title>
</head>
<body>


<FORM action="pippo.php" method="post">


<SELECT multiple size="4" name="component-select">
<?php
...
while ($row = mysql_fetch_array(mysql_query("SELECT ciao FROM tabella",$db)))
echo "<OPTION>$row[ciao]</OPTION>";
?>
</SELECT>
<INPUT type="submit" value="Invia"><INPUT type="reset"></P>
</FORM></body></html>