Here is a bit of code I use a lot
$date = "2002-02-02";
if(preg_match("~([0-9]{4})-([0-9]{2})-([0-9]{2})~",$date,$parts))
$date = date("F d, Y",mktime(0,0,1,$parts[2],$parts[3],$parts[1]));
Basically I split the date up into its pieces (month, day, and year) using the regular expression, then create a unix timestamp with it, then pass it to the date function 🙂
Hope this helps,
JoshB