Seen the movie, but want to read the book? Readers can try online swap sites, too. A great starting point is LibraryThing. It's not a swap site, but it's just about everything else for book-lovers. With its motto "What's on your bookshelf?" it lets you browse members' 36 million books, chat with readers about a staggering number of forum topics (more than 56,000), read and write reviews, and catalog your collection (free for 200 books, $10 a year for more than that, $25 for life). So, after you've browsed the shelves, how to find the freebies? At PaperBackSwap.com, members post 10 books to get two startup credits, redeemable for two books. After that, you earn credits by sending books other members request. You pay to ship the books, but not to receive them. BookMooch.com has a similar setup. Members get a tenth of a point for each book typed in, and one point when a book is shipped to another member. For each three books received, at least one must be shipped off. Both PaperBackSwap and BookMooch include hardbacks and textbooks as well as paperbacks.