Rooting a T-Mo Galaxy S2

So! My friend gave me his old Galaxy S2 (SGH-T989). As a longtime iPhone user, I was super pumped to try out modern Android, but alas, the phone is running 2.3.

I tried updating via Settings and it simply reads "No firmware," which I understand to mean T-Mo never pushed the OTA update to the phone. Is it possible to root the thing and install ICS/JB myself? If so, does anyone know of an idiot-proof guide? Kinda new to this whole process. Thanks.