I found this Calculus book written by Gilberg Strang at the MIT OpenCourseWare. It is free and well written. They say "It is well organized, covers single variable and multivariable calculus in depth, and is rich with applications."
By the way, they have a student Study Guide and an Instructor's Manual available which is even better.
I recommend this book to anyone who is taking Calc I - III as an alternative to their textbooks.