We have several friends visiting the Grand Canyon this summer. It's such an exciting trip, and really makes you ponder the origin of this great canyon.
There are several interesting theories as to how the Grand Canyon was formed, but one that I find fascinating because of it's attention to detail is the theory that Dr. Walt Brown has postulated.
Walt Brown has written the book, In the Beginning: Compelling Evidence for Creation and the Flood, which is now on it's 8th Edition. This is a book that provides a thought provoking and richly detailed theory on many aspects of our origins. Brown's hydroplate theory covers a major portion of the book, and more recently he's provided a detailed explanation as to how the Grand Canyon may have been formed. You can find his entire book on line at this link. Note the table of contents on the left column of that link.
If you are interested in his theory on the Grand Canyon, it starts here, but a better understanding of his hydroplate theory is helpful when considering the information provided on the Grand Canyon.
Another option is to view Mike Snavely's recent DVD endeavor Grand Canyon: The Puzzle on the Plateau. He covers Brown's theory and compares it with other popular theories.