Tap the pencil icon to compose a tweet and then select the Facebook icon.
Enter your status update and then tap "send" to post the update to your Facebook page.
If you have not previously signed in to Facebook via TweetCaster, you will be asked to connect TweetCaster with your Facebook account. Enter your username and password and click "Connect."
Note: It may take a moment for TweetCaster to access Facebook connect - during this time you may see a white screen for a few seconds.