Some neat sites with more info about FreeDOS, and DOS in general.
DOSBox is a DOS-emulator that uses the SDL-library. DOSBox has already been ported to many different platforms. DOSBox also emulates CPU:286/386 realmode/protected mode, Directory FileSystem/XMS/EMS, Tandy/Hercules/CGA/EGA/VGA/VESA graphics, a SoundBlast