Hi Alexa. I recommend www.betterworldshopper.com. They have a page on chocolate, which lists most of the chocolate companies, and rates them from A to F. Nestle gets an F, no surprise there. Perugina and toblerone also get F's.
The best ratings, A+, go to AlterEco, Divine, Equal Exchange, Endangered Species, and Rapunzel.
A and A- grades, go to Dagoba, Shaman, Sjaaks, Theo, Terra Nostra, and Green & Blacks.
I look for sales of the above when I read grocery store ads.
I avoid, like the plague, Nestle, Toblerone, and Perugina, all of which scored an F.
for all the grades and info on the grading system used, go to www.betterworldshopper.com. I hope this helps.