The newly discovered 'SpamSoldier' hides behind links to free versions of Android's most popular games.
Users falling for the scam download apps from a server. They are told to grant the app permission to install and give it the ability to browse the web and send texts. Once installed, that trojan will begin connections to the command and control server. The "zombie" waits 1.3 seconds after sending each message, and checks with the C&C server every 65 seconds for more numbers.
Obviously, you shouldn't be downloading apps from unfamiliar sites, but other than that your best bet at this point: Better hope you chose the unlimited text message plan.