If both PCs have internet access via the Router / Wireless Access Point arrangement, then they are already networked.
You need to set any folders/printers that you want to have available over the network as "shared" in their Properties. They should then appear as shared resources of the appropriate PC in "My Network Places".
If you are running software firewalls, the IP addresses of the networked PCs need to be added to the firewall's "trusted zone".
>>> Also is this also possible with a ibook (i know this is a PC forum !!!) <<<
It is certainly possible, but you'll need someone with Apple experience to tell you how. I've accessed files in a Windows PC over a network from a Linux PC.