The majority of malicious applications target communications, location, or other personal identifying information. Of the known Android malware samples, 55%, acts in one way or another as spyware. The other major type of attack, which make up 44%, are SMS Trojans, which send SMS messages to premium rate numbers owned by the attacker in the background of a legitimate application, without the person's knowledge. Once these messages are sent, the money is not recoverable, and the owners of these premium rate numbers are generally anonymous. (Have you ever considered voting for American Idol via text message and it costs you $1.99 or $2.99 per vote? That's how it works.)
Check out the complete report over at Mobile Malware Development Continues To Rise, Android Leads The Way.