I was looking for a way to change the size of the toolbar icons of GNumeric and AbiWord applications. But I didn't find an application for it (except for the gconf editor).

The solution that worked for me was the follow one:

gconftool-2 --set --type=string /desktop/gnome/interface/toolbar_icons_size "small-toolbar"
That's change the toolbar size of all gnome applications, what was good for me. Sometimes I need more room on my desktop, mainly when I'm using a small laptop screen.

Anyway, for restoring the default large icons run the follow command:

gconftool-2 --set --type=string /desktop/gnome/interface/toolbar_icons_size "large-toolbar"

Is there an gnome application (GUI) to do it ?