Yeah only the new CM7 themes will work with the Theme Chooser. As long as it's an .apk file you just install it like normal and then look in the Theme Chooser and you'll see it. Super easy. Make a backup if your super paranoid or something but it's almost impossible to brick the thing. Even SBFing is SUPER easy. I almost could do it over the internet with Team Viewer. I could almost work at home completely with Team Viewer if I just had one of those awesome Honda Robots. I'm saving up so THIS can be me one day.