I was just wondering whether I could get all my Orkut friends birthday notifications in google calendar so I did a Google search for it. I turned out that @labnol had an excellent post on it. So I am just linking to the post instead of copying and pasting it.
While most Orkut users will definitely find the calendar feature useful, there’re limitations. You can neither subscribe to Orkut birthday notifications in Google Calendar via SMS or email, nor do they provide an XML or ICAL feed for the Orkut calendar so you can’t import birthday notification into other calendar systems.
The only workaround is Google Calendar Sync that will help you import Orkut birthdays into Microsoft Outlook calendar from where you can copy the events into other calendars.
Thanks to Amit Agarwal aka @labnol