Installing GhostScript for Windows
GhostScript for Windows supports PostScript (.ps) and Encapsulated PostScript (.eps) files. You can download it and install it here. To install it, you'll want to download a Windows distribution with an installer (.exe), and follow the installation instructions.
Getting GIMP to recognize GhostScript
To get GIMP, the popular open-source image editing application, to recognize your GhostScript installation, you'll need to set an environment variable in Windows as follows:
Browse to Start -> Control Panel -> System
Select the "Advanced" tab
Click the "Environment Variables" button at bottom
then click "Add" to add the following system variable:
Value: Full path to the location of your gswin32c.exe file (in your GhostScript installation directory - the default location is C:\Program Files\gs\gs8.54\bin\gswin32c.exe, but this may vary depending on where you installed it)
Used to Photoshop, or just starting off with GIMP and having trouble? GIMP is an excellent, open source (free) alternative to Photoshop that is constantly getting better. However, it's not known as the most user-friendly alternative to Photoshop. There is a Windows version available now, which is making it a lot more accessible to the average designer (although most professional designers are on Mac's - which also has a GIMP version). GIMP was originally written for Linux. Visit the GIMP project homepage for details.