This book is available in the public domain in the United States; you may need to check your own laws before downloading in another country. It includes a complete grammar and short dictionary.
I have only formated (added the circumflexes) and designed a cover to use this as a workbook with a group of high school students studying Esperanto this fall. In compliance with Dr. Zamenhof's wishes, there is no royality set on this book. Lernu esperanton!
An audio version is being prepared at www.librivox.com
This is also in the public domain and is available freely.
http://librivox.org/newcatalog/search.php?title=esperanto&author=&status=all&action=Search