Maybe this will help I found it on the web.
Fonts can be opened with Font Book - application. If you have 10.3, it is located in your Applications folder.
You can see the character map on the menu bar. Go to System Preferences, in there to International > Input Menu. Select in that all the layouts you want to use (e.g. US, Italian PRO), and select "Character Palette". Then you will see a small flag on your menu bar to indicate your keyboard layout; scrolling down from the flag you will see character palette, and if you click on that it opens a new window.
Furthermore, many letters like ã ñ ä õ é á ó è à ò etc have a fast shortcut to be done, alt-something, so alt-u and then the letter for ü ä ö etc, alt-n for ñ õ ã, alt-e for é á ó, alt-` for à è ò and so on.