If, like me your digi cam looses the date and time settings each time you take the batteries out and your iPhoto library is full of photos dated 01/01/01, then this link will be of help to you 
http://www.macosxhints.com/article.php?story=20060703160750583
Enjoy!
http://www.macosxhints.com/article.php?story=20060703160750583
Enjoy!