Need to know the birthdate of family members, whether living, or deceased? There are some useful free family history search tools out there that can help you find birthdays.
BirthDataBase is a lookup database that boasts more than 100 million records of birthdates for people in the US. I'm not sure just where the records come from, but they seem to broadly cover births in the 20th century, without any more recent records.
Social Security Death Index (SSDI) has birthday information on about 84 million people. And since they have all passed on, there is death date information here as well.
Two subscription services, Intelius and Veromi, house very large databases that will give you free information on a person's age, though not a full birthdate. Still, it gets you in the ballpark (you can get the actual date of birth for a smallish fee). The free search results will even identify some of the relatives, while you're at it.
Once you find the information you need, don't forget to wish your ancestors a happy birthday.
Visit the main page of Free Genealogy Tools for more, umm, free genealogical tools.
And don't forget to also check for your family history at NewspaperArchive.com, a subscription service, but one of the most powerful research tools available for exploring family history.