The Community College Consortium for Open Educational Resources (CCCOER) is a combined effort to develop and use open educational resources (OER) and in particular open textbooks in community college courses. An open textbook is defined as:
a body of educational content that is openly available over the web, by mail, or in a book store with a copyright that allows copying and distribution or, with the most open copyrights, allows modification of the content and even sale.
CCCOER Open Textbooks provides a growing list of links, covering a wide range of subject areas, to "OPEN and free textbooks that may be suitable for use in community college courses". In some cases, the links also lead to useful podcasts and videos.
This is a great resource. On my first quick look, I found a comprehensive guide to using OpenOffice 3.o!