writing a list of email addresses

I would like to pull a list of email addresses from a group of users, based on certain conditions, then format the list so that it can be used within the mail() function. Am I right in assuming that there will need to be a semi-colon between each address? So far I have: $sql_email = "SELECT email from users where level = 'admin'"; $res = mysql_query($sql_email); while ($res_email = mysql_fetch_array($res)) but I am unsure as to what the next line should be. Any help would be appreciated. Many thanks Peter Gumbrell