This is a great book, as long as you don't read it cover-to-cover. The chapters are self-contained, and there are tons of example programs. When you're learning the language, you can skip around and pick up what you need to know quickly. Then when you get more experience, the chapters continue to be excellent references.
I picked up this book after writing equation solvers in C; and I was able to get up and running in Fortran during a three-day weekend. After about chapter 4, the pace of the book is relatively brisk and well suited to someone with experience in another language.
I also own (and like) Micheal Metcalf's _Modern Fortran Explained_. However, _Introduction to Programming with Fortran_ has many, many more example programs, which I greatly appeciate.
--The introductory chapters are a little redundant; but just skip them, and they won't bother you.
--Some advanced concepts have better coverage in Modern Fortran Explained; but I think Intro to Programming in Fortran covers 80% of the language, and covers it very well.