i'm not a particularly amazing screamer (unlike dev) but i can sing a with similar tone/feel to devin's. the most important thing is to learn to breathe properly and use your diaphragm, NOT your throat, to control volume/power/etc. taking singing lessons from any good teacher will definitely help you, no matter what sound you're going for.
I have been talking with some vocal instructors and discussing this whole genetics factor...most of them says it's bullshit that being a good singer is genetic, and they all recommend this CVT (Complete Vocal Technique) thing, which, according to YouTube, looks like something worth looking into; and in fact something that I wouldn't be surprised if Dev practices...
http://www.youtube.com/watch?v=Sy-QVfHS7v8&feature=related