Vectrex

Dos Vectrex Emulator US Mirror
Freeware emulator for DOS.
http://www.arcadeathome.com/dve/

ParaJVE
Freeware emulator for Windows, GNU/Linux and MacOS X written in Java.
http://vectrex-emu.blogspot.com/

Vectrex
Hardware, Software, Emulator, Tips.
http://mitglied.lycos.de/vectrex/

VecX
VecX PS2 an enhanced freeware PlayStation 2 port of Vecx and VecX/GL an enhanced freeware OpenGL port.
http://jum.pdroms.de/

Vecx
Offers an open source emulator for Windows, includes a brief presentation along with screenshots.
http://www.valavan.net/vectrex.html

Vecx/Mac
A MacOS X port by Richard Bannister of vecx.
http://www.bannister.org/software/vecx.htm