You're right about needing a 'null modem cable'. It's basically a serial cable with a few differences that let the miggy and PC communicate properly. Some stores still sell them with two connectors on each end, a 9 pin and a 25. That lets you plug the 9 pin plug into your PC, then the 25 into the Amiga on the other end. That's the cheapest way to do it, however it's rather slow. You can try a parallel cable, but that is a little more risky - there is some chance of damaging the hardware. By far the easiest way to do it, is with a wired/wireless network card. Your 1200 can support 16-bit 5v wired/wireless pcmcia cards as it is now. The only problem is that it's hard to setup without some sort of connection to the pc already. So, go with the nullmodem cable for now, it's invaluable for getting important files across, etc.
As far as software goes, my vote is for Cloanto's Amiga Explorer. Definately user friendly (guides you through the installation process on the Amiga), easy to use, and you can write ADF's to a blank disk from the PC side, just throw in a blank disk in the miggy, then drag the adf file onto the disk icon on the PC. Easy. :-)
