Wow this came to me as a big shocker, and quite a stupid update. Not sure what Google is thinking with this move. It seems like just a way for them to build up Google+.
- Google Friend Connect—Friend Connect allows webmasters to add social features to their sites by embedding a few snippets of code. We’re retiring the service for all non-Blogger sites on March 1, 2012. We encourage affected sites to create a Google+ page and place a Google+ badge on their site so they can bring their community of followers to Google+ and use new features like Circles and Hangouts to keep in touch.
Taken from their lastest blog post:
So I would suggest you get what ever new system or social networking option you want to move to, and get it setup now so by the time they flip the switch and bury GFC, so you wont be left in the Dark.
Here is a guide that can help you get started with a Google+ Page:
And a Link to the Google+ Badge setup: