The Sisterhood of the Traveling Pants by Ann Frashares
I won't give any spoilers, but I bet most of you have either read the book or seen the movie. The movie is a bit different, but almost spot on. There are only minor details that have been changed in the movie, but they are both very good.
The Sisterhood of the Traveling Pants movie
The movie stars Amber Tamblyn as Tibby, Alexis Bledel as Lena, America Ferrera as Carmen, and Blake Lively as Bridget. They also star together in The Sisterhood of the Traveling Pants 2 movie. I'm not sure if the story line of book #2 and movie #2 match up, but I'll let you know once I finish the book.
Overall, I am loving the series!! I definitely think you should check it out if you like friendship, adventure, and romance (unless you already have!). XO Charlotte