I was looking at this on the website, is it free or is it a must to take a course. If it is a must to take a course I won't be able to get it and would need to know of a free simulation till I get router and switch.
As per its data sheet (http://www.cisco.com/web/learning/netacad/course_catalog/docs/Cisco_PacketTracer_DS.pdf) Packet Tracer is only available to registered Cisco Network Academy instructors, students, and alumni.
If you're looking for a "free" simulator, you may want to examine the boson simulator that comes with most cisco training material. I haven't had great experience with it but maybe it's improved now... You also could sign up for lab time at a local community college. Relatively cheap.