A vaporizer has a heating element (metal, ceramic, or glass) that heats the magic herb to the perfect vaporizing temperature for the THC. You get all the benefits, and none of the carcinogens that you would get for smoke. You dont inhale any smoke, only vapor.

I personally have tried several types and finally settled on the Vapolution. Its a relatively new product sold out of northern California. They cost under $150 shipped, and are built like a tank. They are supposed to be better for you than others because they are all glass on the inside. There is no metal to diliute the flavor. You can check them out at Northern California herbal vaporizers- Vapolution Vaporizer.

The "best" vaporizer is called the volcano, but it sells for about $550 online. I really enjoy my Vapolution more than the volcano. You can find some sites if you google, but be careful. There are many companies that set up sites to hype up their product, and bad-mouth others.

In any case, avoid cheap brands. You can find vaporizers for under $50 in headshops, but they are cheaply made and will burn the bud. There is plenty of information on these forums.