Anyways, getting back to the original story, when I wrote about Facebook subscribe button, I also mentioned about Facebook launching Twitter integration and seems like they rolled out this new feature.
Before you can link your Facebook and Twitter accounts, your app platform in Facebook must be turned on.
I seem to recall reading somewhere that Facebook only checks your Twitter every thirty minutes (or so).
I'm not twittering that much to have this issue, so I'm quite happy with this new additional functionality.
First, you just need to verify your App and Privacy Settings.
Then, go ahead and link your Facebook and Twitter accounts.