Yep, had it done. I'm a bodybuilder and keep most of my body hairless... Also did my ex-girlfriend from head to toe.
Keep in mind, it can take a few months before the process is complete, usually with 3-4 appointments before it is properly done. The reason is, not all hair is there all the time. Some hair has fallen out, or been removed. So you have to wait for that new hair to grow, so it can be removed, and so forth until it is all gone.
Yes it is really perminant. It involves sticking an extremely tiny needle into the pore of your skin where the hair is until you get to the root. Then you give it a small zap of electricity. It's pretty much painless, just small zaps and the needle is painless if done properly as it never pierces the skin. Once the hair root has been killed, the hair itself can be plucked out painlessly, never to grow back.
You'll need a consultation to find out how much it would cost in your area, and to just have your nipples done. (why not your whole chest?).
hope this helps,
justin