Chris on the Hike Alberta blog has been researching the dangers of Nalgene bottles leaching bisphenol.
Goodbye to my Nalgene Bottles | Hike Alberta
Click through if you want to see the details.
It’s the first I’ve heard of this hazard. I normally carry one Nalgene, one soft drink bottle.
UPDATE: Turns out Sarah on the Freezer Bag Cooking blog has already debunked this myth.
Leave a comment if you are throwing away your Nalgene bottle. But first read the other comments.
besthike.com 
There are several different plastics used in water bottles. Not all products by Nalgene, just to name one manufacturer, are made with Polycarbonate/LEXAN. In fact, they make a lot of bottles out of High Density Polyethylene (HDPE), a much less pernicious substance.
Try a Swellz TapSack instead – the exterior is leather and the interior is medical grade latex. The eco-friendly TapSack will be your new hiking partner – it can be carried close to the body and will collapse as the water is consumed – a refreshing idea rather than the extra bulk of a plastic, poly carbonate or metal bottle! Check out our mission at http://www.swellz.com. It has become a welcome addition to our lifestyle.
Be Swellz,
Marsha Nedorostek
Due to the fact that I use a lot of plastic in backpacking I did some real researching and came up with this blog of mine:
http://www.freezerbagcooking.com/myblog.htm?blogentryid=1310588
I have a lot of links to plastic studies on it including this one on Lexan:
http://www.snopes.com/medical/toxins/petbottles.asp
For myself I am not worried, I don’t use a lot of plastic at home, and honestly I feel that there is a small grain of truth and a whole lot of hot air in the anti-Lexan “studies” out there.