Well, assuming that you are using mySQL as a database, something like this:
$query="SELECT email FROM members WHERE name="Joe Smoe";
$result = mysql_query($query);
$row = mysql_fetch_array($result);
echo "<a href=\"mailto: $row['email']\">Mail Me</a>\n";
Of course you would need to modify that to suit your needs...
Matt Wade
http://codewalkers.com