The dollar- Philippine exchange rate today (3/1/12) is 42.722000. In western union branch usually dollar- Philippine exchange rate is lower so if you are receiving dollar money choose to receive the dollar then look for the money changer that has higher conversion.
At SM mall, today the dollar- Philippine exchange rate is 42.50 compared to Western Union branch in Caloocan city that is 41.52. If you are going to use the currency exchange services in SM, you should bring a valid ID such as passport, SSS, etc.and the serial number of the dollar for exchange is needed to be written on the currency exchange form.
I just noticed that the dollar rate in almost the first quarter of the year is low. I hope it will improve in the following days.