I was googling for something and discovered this download on the c5 site for a great user guide (mainly for admin user).

http://www.concrete5.org/download_file/-/12091...

I had already spent a lot of time writing a user guide for my client so I wish I had found this one first -- it's better than mine!

I don't know why there is no mention of this guide anyway (at least I have never run across it before). It is written very well with lots of screen shots -- very helpful for an admin user.