http://www.cs.wisc.edu/~ghost/index.html
or from CTAN in the directory
ftp://ctan.tug.org/tex-archive/support/Ghostscript/Aladdin/ (ghostscript)
and
ftp://ctan.tug.org/tex-archive/support/Ghostscript/rjl/ (GSView)
You will need the files
gs550w32.zip
gs550ini.zip
gs550fn1.zip (all from the Aladdin directory) and
gv26w32.zip (from the rjl directory)