For a beginner I would recommend
http://www.teachmebassguitar.com/index.html
I would also recommend buying the printed version of the book, not just the pdf version. The book will stand up to use.
Even for those not a beginner I would check it out. I am not a beginner and I am very happy I made the purchase. I started at the beginning, but the first few lessons went very quickly, but there was still something new to learn.
There are many features which add to the learning experience, such as the loop feature, where you can have the example keep repeating, and the many different tempo versions. I would also recommend buying the printed version of the book.
The format of the course really help you keep on track, and focused.
