Use PHP date and strtotime :
$formatted = date('d/M/Y', strtotime($date_from_mysql));
Or use MySQL built in DATE_FORMAT :
SELECT DATE_FORMAT(datetime, '%d/%b/%Y') datetime FROM table
Or, you can mix a little of both flavors:
SELECT UNIX_TIMESTAMP(datetime) timestamp FROM table;
$formatted = date('d/M/Y', $timestamp);
The last method is convenient if you need to get several different formats on one page; let's say you want to print the date and time separately, then you can just use the date ('d / M / Y', $ timestamp) and the date ('H: i', $ timestamp) without any further conversion.