Sql limit

hi, got a sql statement, prettystraight forward:

$sql = "SELECT Psuburb FROM WB_listings ORDER BY Psuburb ASC";
//Create recordset called $rsstock
$rssuburbs = mysql_query($sql,$connect);
//Find out how many records in the recordset
$rows = mysql_fetch_assoc($rssuburbs);

everything works fine… BUT. in my Psuburb column there is multiple entries for one place, ex. 5 Durbanville’s, 10 Kraaifontain’s, etc… I only want to display one of each. i.e. this displays in a dropdown list on a property website, so the people can search what propeties are listed in the different suburbs.

I’m sure this must be very easy, I’m just missing something.

Hope you can help!