Emulator: Atom Emulator v1.33  ** Recommended **
Author: Wouter Ras
Platform: PC / DOS
Homepage: http://www.homepages.hetnet.nl/~wouterras/atom.htm (dead link)
Homepage mirror: http://www.stairwaytohell.com/atom/wouterras

Emulator: MESS
Author: Various
Platform: PC / WINDOWS (others available)
MESS Homepage: http://mess.emuverse.com

Emulator: Atom Emulator v0.3
Author: Frans Faase
Platform: UNIX etc
Homepage: http://home.wxs.nl/~faase009/Ha_Atom.html

Emulator: Atomac 0.8.1
Author: Julian Skidmore
Platform: MAC
Homepage: http://www.p-skids.freeserve.co.uk/#Atomac