Woo~ Yeah, I have a handful of the "Japanese for Everyone/Minna no Nihongo" textbooks. I lived in Japan for a year and attended a weekly class for learners, and that was the book they recommended. It was so great because there were grammar notes for English, Spanish, Chinese, ANYTHING. I picked up the second level book, along with writing, listening and reading practice ones. ^_^
I can't say that I've ever seen them in an American store, though. :O I'm glad they are! Sadly... I've found the best place to buy books to learn Japanese is... in Japan. ):
OH! Use http://www.bestbookdeal.com to help you find great online bookstore deals! If any learners have trouble finding the book you want in a store, I'm certain this site will help you out!
Have a textbook or grammar book that you find particularly helpful? What about a learning tip to share with others?