Before the Migration Assistant can work your Mac will have to be able to 'see' the PC. That they aren't both wireless isn't an issue unless they aren't on the same subnet. An IP address looks like this: 220.127.116.11 and your two computer IP addresses should be the same for the first 3 sets - only the fourth should be different. And the fourth must be different. Still it would be best if both were connected via cable because wireless will be very slow if you have more than a couple GB of data to transfer.
You may find this article helpful to get FileSharing set up between the two computers.
I followed the link to the article you suggested. Everything went according to plan until Migration time, and still, my iMac will not recognize my PC (or vice versa, I have no idea). Not much IT experience here. Giving the PC to the wife, I have many files from my voice acting work, and still no solution. But thanks so much for your responses.
There may be something useful here:
How to use Migration Assistant:
Troubleshooting Firewire target disk mode:
File server & Migration with a PC either works or it is a &#%! to get going. I am in IT so in the end I've always gotten it to work but there've been times when I've used a few choice words at Bill Gates & Co. Your other choice, of course, is to use an external drive to copy files from the PC to the Mac. You'll need a backup drive anyway. Unless you buy a Mac specific drive (and there's no reason to) it will be pre-formated for Windows and that's okay. The Mac will be able to read the files. Copy all your documents, music, video, etc and then drag them to the appropriate folders on the Mac. You can reformat the drive for TimeMachine once this is finished.