PCVIC
   Upgrade your PC to a VIC-20. Runs on MS-DOS, OS/2 or Windows.
   http://wwwhome.cs.utwente.nl/~schooten/software/pcvic.html

Pfau Zeh
   VIC-20 emulator for Win32 and Linux.
   http://www.classicgaming.com/pfauzeh/pz_main.html

Power20
   VIC-20 emulator for the Mac OS. Shareware, fully functional for 10 minutes until registered.
   http://www.infinite-loop.at/Power20/index.html