Google Friend Connect is officially open for everyone, it allows you to add social gadgets to your site. Using friend connect any one can join your site with their existing Google, Yahoo, AOL or OpenID accounts.
You can join from here, and then setup your site, you need to upload two files (“canvas.html” for gadget and “rpc_relay.html” for security features) to your server and get the code for members gadget or other social gadgets like comments or review/rate gadgets. You can join “Technology Bites” by using the sidebar friend connect gadget.
From Google Blog
Friend Connect’s goal is to facilitate an open social web. Using open standards like OpenID and OAuth, Friend Connect makes it simple for people to instantly interact with one another on the sites that they already love to visit. Additionally, websites that use Friend Connect become OpenSocial containers, capable of running applications created by the OpenSocial developer community.