What is Hoodia gordonii?

Could you please tell me what Hoodia gordonii is and are there side effects?

Hoodia gordonii is an African cactus plant that kills the appetite. It is sold over the internet as an aid for obesity. There are no known side effects, but clinical trials on this plant have just begun.
According to the BBC (see: news.bbc.co.uk/1/hi/programmes/correspondent/2947810.stm) it is currently illegal to export this plant, and diet pills sold over the internet have "no discernible Hoodia" in them.