Good question. I used to be able to do it by installing a Birthday program for my Handspring Visor. I would enter it into my address book and it would provide upcoming birthdays in my Date Book and To Do List. This would also sync with iCal and provide an alarm and everything.
Don't know if you have a Palm PDA of some sort, but you can download a program to do this for you if you do.
Have you gone to versiontracker.com and searched for such a program that allows this functionality?