So stop smoking pot and get one of <a href="http://shop.grasscity.com/shop/grasscity/vapormed.html">these</a>.
Yeah, it's $600, but if you value your lungs and you smoke a lot of pot, it's worth it. Instead of burning the weed, it bakes it so that the THC is vapourized, resulting in much less tar. A few of my friends own one and some have actually quit smoking altogether (both tobacco and pot) since they started using the Volcano. There's also a smaller, less expensive vapouriser called the Vapir (~$130), which has a digital temperature sensor so you can hit it right when the THC is at vapourising point.
Also, THC has been scientifically proven to protect against cancer, mostly if it's consumed by methods other than smoking, ie brownies, cookies, rice crispie squares
Beware, though. The Volcano will get you more baked than ever before. First-timers have been described as "virgins sacrificed to the Volcano."