I wrote this tiny script to check b'days of my friends and send greetings. Of course the greetings are random and customizable...and you can ignore friends that you don't want to greet (though I don't use this feature :)
You need to have working FBCMD and python installations. Setting up is just as easy. Add it to scheduled tasks or anacron or whatever and you have a personal assistant to greet friends everyday.. enjoy !