<select>
<?php
for ($i = 0; $i < 4; $i++) {
    echo '<option value="' . date("Y-m-d", strtotime("this sunday - $i week")) . '">' . date("M j", strtotime("this sunday - $i week")) . " - " . date("M j", strtotime("this saturday - $i week")) .'</option>';
}
?>
</select>