Scandoublers are pretty expensive, but they are the total solution to using PC monitors.
The other solution is to get an adapter so you can plug in a PC monitor straight to the Amigas standard video port. Then you just need to use a monitor driver like MULTISCAN, VGA, DBLPAL, etc.. This is only good for Workbench software, or software where you can select what screenmode you want to use. Most games will not use Workbench monitor/screenmode settings. And also the startup screen will not be viewable (when you hold down both mouse buttons when you power on).. that screen by default is 15KHz PAL or NTSC.
I think I got that correct.. feel free to correct me anyone.