Wikibooks made an appearance in this month's Computer magazine. The article was titled: "Wikis: 'From Each According To His Knowledge'", by Dr. Daniel O'Leary of the University of Southern California.
The article (for which a link to an online version is currently not available) is part of a small series called "The Pervasive Web", and serves as an introduction to and an overview of wikis. It does not focus only on Wikimedia or even Mediawiki projects, but it does have the several obligatory references to Wikipedia. Unlike most articles on the topic of Wikis, this one also includes mention of the Wikimedia Foundation and the various sister projects. It mentions, by name, Wiktionary, Wikibooks, Wikiquote, Wikisource, Commons, and Wikinews. Judging by the references and citations, I estimate that this paper was originally submitted early in 2006 (so it wouldnt include mention of Wikiversity). It also mentions Jimmy's other project, Wikia.
The paper includes a few images: Ward Cunningham's original WikiWikiWeb, SAP Wiki, and an image of Wikibooks. It's significant because he didn't use an image of the more well-known Wikipedia when he wanted to provide an example of a WMF/MediaWiki project. He also includes some information drawn from Wikibooks, including excerpts from our copyrights policy, and our use of graphical progress indicators to demonstrate the progress of our texts.
This is, I think, a great indication of the name recognition and stature that Wikibooks has gained in the past year. Many people, especially professional educators and researchers are seeing Wikibooks as a viable and beneficial project.