I3astards,
No prereq to CCNA, can do the 1 or 2 test option.
I would get 2 books, Sybex CCNA Study Guide by Todd Lammel and one of the Cisco Press CCNA books, Wendell Odom is one of the better.
Between the 2 books the Lammel book will give you what you need to know for the exam and the Cisco Press books tend to go into more detail so you understand it a little more and can work with it.
It also helps to have 2 different perspectives.
The CCNA is a lot about troubleshooting - a sim like Cisco's Packet Tracer is good, an emulator like GNS3 is better and a home lab of real equipment (3 routers and 2 switches) that you can do end to end networking is the best, a place where you can try all the different commands and labs!! Using all 3 to get hands on PRACTICE,PRACTICE and MORE PRACTICE is the BEST !!!!!
HANDS ON PRACTICE, as you read about it get in the lab and try it. Here is a link to Wendell Odom's blog at Networkworld about setting up a home CCNA lab -
Study the material, take practice tests and use those to determine where you are and go back to the areas that you don't do well in.
DO NOT JUST LEARN THE PRACTICE TESTS !!!! Use them to understand where you are at in your study!!
As far as how long it should take depends on how much time you have to put towards study, it could take a few weeks or almost a year, when you know the stuff in the books and on Cisco's CCNA exam blueprint like the back of your hand - take the exam !!!
Good luck and I hope this helps !!
E.A. Broda
CCNA, CCDA, CCAI, Network +