Hi,

In Germany the first scientific book about Wikipedia has been published:

Frost, Ingo: Zivilgesellschaftliches Engagement in virtuellen Gemeinschaften. Eine systemwissenschaftliche Analyse des deutschsprachigen Wikipedia-Projektes. München: Herbert Utz Verlag, 2006. 152 S., € 29,00. ISBN 3-8316-0609-9

It's the diploma thesis of Ingo Frost, accesible at http://www.cogsci.uos.de/~ifrost/ an english abstract is at http://www-lehre.inf.uos.de/~ifrost/offiziell/engl_abstract.html Wikimedia Germany has supported the printing.

More scientifc works of Wikipedia research can be found at http://bibliography.wikimedia.de/

And it's getting more with Wikimania and WikiSym conferences in August.

According to his weblog Andrew Lih is writing a book about Wikipedia so you will also get a book in English, but we were the first, afaik ;-)

Greetings, Jakob