Hi Amanda,
I recommend a book that Tandy sells called 'Leatherwork Manual'. It was written by Al Stohlman and two others, and was designed as a class textbook for basic leatherwork. It starts off with casing leather, works through the basic tools for stamping and carving, and even takes you through several basic projects. It was the book I first stared with and it really teaches you a lot. It's not very expensive and will give you a good start in leather working.
Hope this helps,
Bob