There are many places full of wonderful information available.
I would highly recommend The Womanly Art of Breastfeeding from the La Leche League International to any individual who is considering breastfeeding. It is an easy read with tons of information and has amazing troubleshooting tips that can be searched in the index!
Kelly Mom Parenting and Breastfeeding is a great resource for pregnancy, breastfeeding, and parenting through all ages and stages.
Most states offers laws protecting the breastfeeding mother and allowing them to feed in public without consequnce. These laws, by state, can be found on the National Conference of State Legislatures website.
Lactation consultants can be a very helpful resource when a mother is struggling with breastfeeding. They can help to identify common problems that lead to a difficult time with breastfeeding. The International Lactation Consultant Association is a great place to find such consultants.