There are enough online resources available to encourage you prepare for CCNA. I would suggest get your hands on ICND1 and ICND2 books written by Wendell Odom. These two books are very well detailed and provide you a great insight to CCNA and teach you everything you need to know to pass CCNA.
There are other resources that could be of immense help while preparing for CCNA like Chris Bryant Video Boot Camp. And Pual Browning new site howtonetwork.com.
Make sure you install GNS3 on your machine. It is a unique graphical network simulator. You would need ISO images to be able to use the routers in GNS3 and you can find them online. There is one thing that no software simulator can provide, a full switch mode you would need a real cisco switch to practice some of the commands.
For the well-know port numbers click here.
