There are a lot of good PSX emulators but only a few great ones, with ePSXe being the greatest one, at least in my book. It reigns in compatibility but lacks a good user interface, this is where AdriPSX ILE edition comes in, it has a great GUI and reigns in easy of usage...
Head over to
http://www.psxfanatics.com and download their PSX emulator installation packs... Also
www.ngemu.com is a good resource for PSX emulation in general.