There really isn't. Linux sysadmin skills come with the knowledge of using Linux. One book, or even one application would be huge if they were to cram that much knowledge into one space. The best thing is to get a Virtual Machine application (VMware, Parallels, etc), and install a Linux system, and go through how-tos, or even a book of basic usage (Linux LPI Exam books are great for this). After you have the basic knowledge, you can always find a book on administrator tasks/practices.
As for the Cisco simulator, remember these are NOT fully functional emulated routers. They only allow you do a handful of commands, which relate to the question, or lesson being taught.