As this article may be read by Windows and OS/X users looking for information...
1) There is a Windows port which installs easily and seems to work. http://wiki.gnucash.org/wiki/Windows
2) GNUCash can be installed on a Mac using DarwinPorts. However it's a struggle, or it least it was for me when I did it eight months ago. http://gnucash.darwinports.com/ (scroll down the page for instructions) »