I don't know if this has already been posted or not as I haven't been following the thread lately, but I guess it deserves to be posted twice.
MIT is launching the OpenCourseWare program making its course materials free. http://ocw.mit.edu/index.html
I am collecting information in preparation for construction on a small particle accelerator. In my resent searching I found this book "Principles of Charged Particle Acceleration" http://www.fieldp.com/cpa/cpa.html. It should be helpful for me and hopefully someone else out there.
This is the 6th edition of Biology by Campbell and Reece, the text we used in my General Bio course. The user name and password are chocolatejesus12 and jenny21. They still work. It has the complete text (under e-book) as well as pictures, diagrams, and activities you can do.