Also, Angela, two things that I would HIGHLY recommend when learning about wild mushrooms is, first, get more than one guidebook to wild mushrooms ("more than one", because no single book is nearly complete or comprehensive when it comes to wild mushrooms in Alaska), and read it, look at the photos, and generally go through them a LOT.  

Secondly, and don't dismiss this suggestion, you really have to learn the Latin names of the wild mushrooms!  Many if not most of them do not have a single, or any, common English name, and if you are going to try to look them up in various guidebooks, or online, it is imperative that you use the Latin name, or you simply will end up confusing and frustrating yourself, as you won't find nearly as much information on them as you would otherwise.