Wireless connection difficulty

As you can see I am a "newbie" on the iMac, however I really have fallen in love with it. Further, I am not very computer savy, but here is my problem: I can't get the iMac/PC combination to run as a wireless LAN (if that is the correct description). I want to be able to access the files on my PC and even move the iTunes content from the PC to iMac.
My system/equipment is:
1) I have a PC running XP Home edition
2) I have broadband internet connection thru a "Speed Stream" #6520 modem, which has a wireless router (supplied by Aliant when the broadband was setup).
3) I have been able to connect to the internet on this wireless network from the iMac.

I need information on how to connect the iMac to the PC wirelessly. Hopefully this can be specific "step by step" instructions by someone here or point me to a resource that will give the information I need.

Many thanks.

 

Forget prior post. Seemed to have solved it. Was that PC not set up properly I think. However, I did it without setting the workgroups the same on both computers. How this is possible I don't know. Also, it let me on as a "guest" but would love to be on as the "registered user" Further, I can't seem to find how/where to name a workgroup. Any suggestions for these (2) issues?