Welcome to Mr.Excel!
It's definitely a good source to reference as you go along. I signed up for the chapters via email and after Chapter 1, I had to buy the book.
You may also want to consider the Shelly Cashman Series of books to get you started. Other than that, a large part of learning Excel, as any other program, is actually using Excel.
You will definitely have some questions along the way, but no matter how unintelligent they may sound to you, dont be afraid to ask them anyway. By joining this forum you are already on the correct path. Through this community, you have direct access to the Excel experts. Im a newer member myself and I wish I would have discovered this place long before.