Some official, some unofficial, try these links for more information on books and comics. Links to authors' websites can be found on the individual bios in the Authors section. If there's a link you think should be up here, please email me.
 

The Official Site - starwars.com is the official Star Wars website, and now has a rather cool EU section.

The Official Del Rey website - for info on the latest books, straight from the publishers - scroll down and click on 'online catalog' and/or 'sample chapter archive' for useful stuff.

The Official Darkhorse website - excellent site from the comics publishers - click on entries in their timeline to look at covers and read more about comics and graphic novels.

The Official Scholastic website - publishers of the 'Jedi Apprentice' series, as well as a bunch of other SW books - nice site.

Official Dorling Kindersley website - published several 'kids' books, including the excellent Visual Dictionaries. May take some searching, but you can track down samples, etc.

The Unofficial NJO Homepage - recommended for NJO fans - beware spoilers!

The Star Wars International Booklist - quirky little site that lets you take a peek at the novel covers available in countries around the world.