Aqua-Soft Forums[request] Who Can Tell Me How Can Change This Icon
It is defined by two png's. On my computer, they are located in "usr/share/icons/hicolor/36x36/apps/" and the png's are labeled "gnome-spinner-rest" and "gnome-spinner". I'd imagine that you can add these two icons to your icon set in ~/.icons or in ~/.themes. Never tried it, but that's where the png's are located. Good luck.
Go into gconf-editor, and find the Nautilus folder. One of the choices will be "Throbber".