Only day and month

Hello,

I made a form with the date of birth from persons (and also their adress, phonenumber,etc). What I want to do now is to use this date, but only the day and month, and not the year, so that I can sort that list and only have their birthday during the year.
When I sort now on the DOB, I first get the oldest one (or the youngest), but I want to see when a birthday is due during the year (for example: who's birthday is in May).
I tried the scripting, but I can'tfigure it out.
Help!
jobrac