Here are some textbooks and individual units that I use in my courses. Instructors at other colleges and universities are free to use them with attribution. Simply send me an e-mail giving me your name, institution, department, course, and what you plan to use. THANKS, and enjoy!
by H. Joseph Straight and Julia M. Wilson
This is a text used at SUNY Fredonia for our MATH 210 course. Individual chapters are available in pdf format.
by H. Joseph Straight
This is the text that I use at SUNY Fredonia for our MATH 231 course. Individual chapters are available in pdf format.
These are some Maple examples that I use in our MATH 125 Software for Mathematics course.
Smokin' Joe's Catalog of Groups
A catalog of all the groups up to order 31. This link is currently disabled; contact me if you're interested in this resource.