Google’s short URL service is live and working fine thru Google Toolbar and Feedburner. So here is the tutorial to show how to use Feedburner Socialize feature to share post feed on twitter “Auto-magically”. 
Let’s start with the settings on Feedburner to activate this service,
1. Go to your Feedburner account and Select your feed Item i.e. Title from My Feeds
2. Go to the ‘Publicize’ tab in navigation
3. Click on ‘Socialize’ tab on left panel
4. Click on “Activate” at the bottom of the window to activate this service
5. Now you can customize from the options on the same window to Show/Share posts on twitter directly from your feed.
6. Shared URL will be in newly launched goo.gl service. You can preview the posts ready to share on twitter on he same window
Screenshot of Socialize Window on Feedburner
Add some additional text such as “Blog’s Name” on Additional Text box to brand your blog on twitter. You can also hash tags to increase the hits on your shared item on twitter.
Related: Complete Analysis Of Email Subscription On Feedburner