Boxcar is a useful application for iPhone, iPad and iPod touch. This application allows you to enable Twitter push notifications for free. Boxcar can be set to automatically open your Twitter application when a push notification is accessed.

If you are interested in optimization of your Apple's product, here are the steps to install and configure it.

Find more - http://livestreamsblog.com/2010/08/30/iphone-4-tips-n-tricks-iphone-push-notifications-through-twitter-application/