Well, it seems to depend on the pills. I smoked half a 98 Mitsubishi once (in a joint, with some hash), and was UTTERLY FUCKED. I'd already been out and had 1-2 (I think), and fancied giving it a bash, because I read about it on the old board.
The high was quite different, much more intense, but much shorter lived.
I spoken to others who have done the same with other pills and that got nothing out of it. Apparently, you can smoke them by 'chasing the dragon', heroin-style. Don't ask me how, because I really don't know.
Out.