This comes up too often...
Simple answer- yes, you can damage your throat if you push too hard in any vocal style. The one described from the gut is room level growling which is what Mike does according to Lee_B. It's not the only way to growl without hurting yourself though, and in my opinion it's best to know both styles. If you do room level growls in real life, people will laugh at you(no seriously, it sounds ridiculous out of the mix- at least with mine).
Anyway, I JUST posted on this in the Andy Sneap forum yesterday so I'll just copy that instead of typing it all over.
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I'm gonna do all of you a big favor now and post a little guide I wrote up a while ago. The biggest problem with threads like this is no one ever explains how to get that feel in your throat- they just expect you to know and then people end up killing their voices. Everytime I've posted this people have been all "holy shit that WORKED!!!" and once you've gotten the feel for this then you can practice and get good at it instead of practicing damaging your throat.
"The key is to feel the gurgle in your throat, as this is what makes the sound. The proper term, is "vocal fry." Yknow that rasp you hear in metallica style singing?(think sandman) THAT'S vocal fry.
Start by talking like you've just gotten up in that morning, with a grog in your throat. Don't push much air out. Just groan, or say "oh I don't wanna get up." or something. Then use that to sing a bit. Don't push the air while your singing. The force of the air creates a clean tone, so by lightening this you make a pleasant rasp. You should really be able to get a feel for hard rock singing in a few minutes, I'm not saying you'll be in tune- but the rasp should now be there. If you do plan on singing this way, be sure to practice clean as well since many singers can't sing a clean tone if they sing this way too often. The growl won't affect that though.
Alright, here we go- take that rasp and drop down a few octaves in your voice. This should REALLY give you a feel for the growl. From here, you should be able to feel it in your throat, and learn how to control it. If at first you can't do it automatically just refer back to "oh I don't wanna get up" with very little air, and drop right back into that growl. Practice changing tones, and experimenting with octaves. Find what's comfortable for you and make use of it. It's been my experience that people tend to be comfortable with some ranges and uncomfortable with others. I know my black metal scream is pretty crazy sounding, and it's consistent in that range. My younger brother, who I taught to scream, has a low brutal death growl and his voice is higher then mine in real life- so go figure. The point is that once you feel that gurgle you should be able to experiment and feel whats comfortable. Make sure to try switching to a high(black metal sounding) octave while maintaining the rasp at least once to see if you like it. Practice when you can and soon you will be able to go longer without dryness in the throat. You should IMMEDIATELY notice that you will no longer be sore back there like it can get if you just scream as loud as you can. As long as you don't push too much air(to the point where the tone almost becomes clean) it's unlikely that you'll damage your vocal chords. In fact, it should be no problem to switch from a growl to clean singing. Practice makes perfect though, so if it's possible- try recording yourself as well, and adjusting it to the way you would like it to sound.
Remember, don't push your throat too hard. It won't make it any heavier sounding and you could hurt yourself."
I hope that helps guys, just please don't rip the crap out of your throats. Here's a clip of me to show how I sound after a little over a year of knowing how to do this and practicing on and off. It's a shit song, but a decent vocal sound. Also(as if you can't hear it

) I double tracked everything but the huge shriek near the beginning.
http://elboardo.com/amir/cheddardeath.mp3