Celiac Disease Foundation Typically the first place your doctor will tell you to go once you've been diagnosed. This was my first stop too. I find it helpful and informative.
National Foundation for Celiac Awareness A good place to research symptoms and get access to medical information.
Celiac Sprue Association A bevy of great information on conditions and symptoms as well as a kids site and lifestyle sections.
Celiac.com Another website with an abundance of information. I find it a bit overwhelming at first but just breathe and poke around for a while and you will find lots of helpful information.
gfco.org This is the Gluten Free Certification Organization. It has a search and drop down list that is good if you know what your are looking for or want to double check a certified product.
Celiac Chicks This is a great website if you are in NY or the surrounding area. I found it difficult to navigate at times but I am impatient! It has a lot of great information and they have a long history of providing gluten free information.