Things I've noticed:
1) DailyLit. Their premise: while lots of people don't feel that they have time to read books, everyone has time to read their email. DailyLit will email you books in installments sent as often as you wish -- out-of-copyright books are free, as are those distributed under a creative commons liscence, while books still in copyright cost a small fee (less than buying the actual book). I'm currently reading Agnes Grey, by Anne Bronte, in 82 daily installments.
2) Wordsy.com. Think Digg, but for authors, publishers, word nerds, and book lovers. It's neat-o.
3) BookMooch. I've had a link up for a while -- I've even had an account up for a while -- but it's only been very recently that I've started participating. The idea is very simple: it's a worldwide fora for exchanging used books. You list books you wish to get rid of; other users request to mooch your books; you mail them the books in question. You pay shipping to them, and you receive books for free. (You can also choose whether to send internationally or just to your own and/or neighbouring countries, which can help to mitigate the cost). It may be easier to get some books from the library -- but if it's something hard to find, or something you'd like to keep for yourself, BookMooch is a very useful place, methinks.
4) TOC About Writing. This is a webpage put up by the Science Fiction and Fantasy Writers of America, as a one-stop shop for all sorts of advice on writing, editing, and submitting your masterpiece. And most of it is pretty funny, too.
5) Medieval Book Curses! Now you know what to write on your ex-libris page to really prevent your books from being stolen . . .
6) Ex-Libris: a cool e-zine for librarians. I like it.