Sarah Houghton- Jan from the Librarian in Black blog has posted a new site Research Beyond Google
developed by Jimmy Atkinson. The site is a wonderful overview of the basic invisible web resources, that every librarian should be familiar with.
In my opinion though, the Deep Web is still very invisible, although there are technological advances in the modern search engine spiders and crawlers. To learn more about the current state of the invisible web(web pages and databases not accessible to search engines) read the wikipedia article about the Deep Web.
Source: Librarian in Black