In a similar vein to RobR's post on elibraries (http://www.mobileread.com/forums/showthread.php?t=1908), there's a site called http://www.knowbetter.com.

It's huge, and has features like ebook-related news, an ebook directory to make it easier to find that title you're looking for, an ebook libary with over 2000 titles available for borrowing (though I believe you have to pay a membership to access this feature, $19.95/year).

It's worth a look.

Craig.