In order to earn money from the premium-rate SMS, the trojan will fake itself as a famous app, like Angry Birds; or downloader/installer of well-known softwares, it looks like 'real thing'. Some of these kinds of apps appear on the third-party download sites, and some will repackage itself, post to the official Android Marketplace, and try to lure innocent people to install it.
The malicious attackers have bundled the premium rate SMS trojan into a fake copy of the popular app Angry Birds. Upon execution, the trojan seems permissions to sent SMS messages. Once the user confirms that the application is free to do so, the trojan will start sending premium rate SMS messages to multiple numbers outlined in AegisLab's post.