I just passed my ccna on the first try it was the 640-607 test which is now being replaced by the 640-801, but I thought that it might be helpful for some to see what I used to study. I taught myself I really havent had any contact with anybody who has any sort of knowledge in this field except for an intro to networking class in college. Subnetting I found to be very simply explained at http://vanier.mjcatholic.ca/~clapoin...-explained.htm
This doesnt include every aspect of ip addressing that you need to know but i found it to be an excellent starting point. I hate to suggest other discussion forums but I found the posts at http://www.techexams.net/index.shtml to be very helpful. By far the best resource was Celtic Rover at http://www.celticrover.com/tig/ccna/ccnareviews.asp I found this to be very helpful and if you can successfully pass the exam practice questions on this site than you will do just fine on the exam. I also thought that http://users.froggy.com.au/djjit/tips.html was very helpful to as it helped me to get an idea of what things I had forgotten to cover. My router sim was boson which I thought wasnt of very good quality but allowed me to practice enough to do well on the router sims on the test. For text books i would have to recomend Todd Lammle and Sean Odom's book CCNA exam notes. I also thought that Chiarella's book CCNA self-study guide was well written also and i would recommend that it be read before Todd Lammles book as his was a little bit more technical. To have access to Cisco's exam study information was helpful also as a supplement to what the study guides dont cover well. I would recommend the ccna certification for anyone interested in networking as i learned an enormous amount of stuff that I had always wondered about.