Stuck on basic concept, how to use a list selection?

I want to: Populate a dropdown list with values from a MySQL db (done and working). Use the selected value as the 'where' clause in a second query. Return the results and display them to the user. Any pointers are appreciated - noob^3 (html, mysql, and php). Doug Code that I'm using: <html> <body> <?php // connect to db $db = mysql_connect("localhost"); mysql_select_db("test",$db); // build query $sitequery = "SELECT site from sitedata order by site"; // generate result set $siteresult = mysql_query($sitequery); // use results echo "Select a site from the list below: <br><br><select name='site'>"; while($siterow = mysql_fetch_array($siteresult)) echo "<option value='".$siterow["site"]."'>" $siterow["site"]."</option>"; echo "</select></td>"; ?> </body> </html>