linux usually does not have just one font directory like windows, which i consider one of the features of windows. there are many font directories.
if you want to know where your consolefonts are:
should be pretty much the same on all distros but i am not sure. if not 'find' them:
find / -name consolefonts, or
find / | grep consolefonts
for the location of your X11 fonts see /etc/X11/xorg.conf. there's a section "Files". it lists the font paths. in my case:
OpenOffice (further OOo) however has it's own font dir in <OOoDir>/share/fonts/. the *.ttf's go in truetype/...you can add the fonts manually by copying them in <OOoDir>/share/fonts/ or you can use the spadmin program that comes with OOo. it's located in <OOoDir>/program/