This practice was discussed on Anderson Cooper yesterday, and I posted a link on the FB page: http://www.andersoncooper.com/2011/09/21/placenta/
It was also the topic of a piece in NY Magazine: http://nymag.com/news/features/placenta-2011-8/
The placenta is a source of many nutrients, and some people find it helps them recover from post-partum depression.
So -- are you planning to consume your placenta?