I really wanted to write this post from a long time. But with lack of Blogging time i can’t post. Most major Web companies – Google, Yahoo, Microsoft, etc. – have announced support for OpenID, meaning that you can use your credentials from any one of those services to register and login to third-party websites that support OpenID. But Facebook is taking a big leap beyond all of these companies today by enabling you to login to its own site using either Gmail or OpenID.
That means You can now link both your Google Account (including Gmail), MySpace, Yahoo ID and OpenID with your Facebook profile.
The advantage of linking you other online accounts with Facebook is that if you are signed-in into any of the above services, you'll automatically be logged into Facebook as well. So for example, if you working in Google Docs or writing scraps in Orkut and then decide to open Facebook in another tab, you won't see the Facebook sign-in screen anymore.How To Link
To setup this association between Facebook and Yahoo/Google Accounts do the steps written below.
Step 1. Login to your facebook account,
Step 2. Go To Account Setting,
Step 3. click on Add a new linked account,
Step 4. From the pull down menu Select your preferred service,
Step 5. Facebook will send you to selected service's authorization page,
Step 6. Once you’ve authorized the connection your two accounts are linked!
One last thing Facebook lets you link only one account per web service so choose the ID that you use most frequently on the web.