Your first question...The passing mark for the CCNA exam is 849. Don't let that scare you though because the grading scale goes from 300 points to 1000 points. I recently passed my CCNA exam so I know exactly what you are going through. There are several things you can do. There are literally hundreds of place you can go to get free practice exams. I read Wendell Odom's CCNA book it was quiet helpful. Make sure you are proficient in IP address for there will be A LOT of questions on it. www.testking.com is a very very helpful source. That is what I mostly studied from. It has 392 quetsions and most of them are very closely related to the actual exam. But, like everything in this world, there is a price to pay. You will have to register and then buy their CCNA exam. I believe the cost is $39.99, but it's well worth it becuase the test fee is $125 and you don't wanna take it again and pay another $125. Hope this helps.
There is nothing as good as having a good practice with simulators since you are going to meet them in the actual exam. Also, a solid grounding in TCP/IP will go a long way in helping. Tesking's Crams (www.testking.com) are excellent preparatory questions; but you must have lots of reading of CCNA books.
I would like to add one more thing. You are going to have two or three simulations in your exam. Most of the times they are about troubleshooting routing protocol (rip) or assigning IP address to intrefaces. You have to focus on these topics: access-lists, subnetting, switching, routing and OSI model. I advise you to join this group http://groups.yahoo.com/group/CCNA-Group .
