Question says it all. I need them to be available in gimp.
Many fonts are packaged for Ubuntu and available via the "Fonts" category of the Ubuntu Software Center. If you prefer
apt-get, search for packages starting with otf- or ttf-.
Font files that are placed in the hidden
.fonts directory of your home folder will automatically be available. You can also place them in the
~/.local/share/fonts directory on newer versions of Ubuntu per the comments below.
You can also double-click on the font file (or select Open with Font Viewer in the right-click menu). Then click the Install Font button.
If you need the fonts to be available system-wide, you'll need to copy them to
/usr/local/share/fonts and reboot (or manually rebuild the font cache with
fc-cache -f -v).
You can confirm they are installed correctly by running
fc-list | grep "<name-of-font>"
You may need to restart some programs, like OpenOffice Writer, before they actually show the new fonts (usually such programs are caching the font list when they start up).
Edit: Changed advice to manually install into
/usr/local/share/fonts instead of
/usr/share/fonts to reflect comments and best practice.
Copy the fonts to
/usr/local/share/fonts or a subfolder (such as
/usr/local/share/fonts/TTF) and then run
sudo fc-cache -fv. There are some graphical programs you can install to make this easier, but I've never felt the need to try any of them. The Ubuntu wiki page on Fonts here may be of help too.
GIMP will find them in there then.
You don't have to install as root. Create a folder called
.fonts in your home directory (if you don't already have one), drop the font file in there, run Gimp, job done.
(You may have to enable Edit->Preferences->Views->Show hidden and backup files in Nautilus to be able to see
.fonts and other ‘hidden’ folders in your home, if you haven't already.)
Application for Install and Manage fonts.
Can install Multiple Fonts.
To install fonts Click on Manage Fonts Button and select Install Fonts Option.
Font Manager can be installed from apps.ubuntu.com or and with Software Centre. If with commandline ;
sudo apt-get install font-manager
Fontmatrix is a real Linux font manager, available on any platform and as well for KDE (which already had Kfontinstaller) as for Gnome. It's purpose is to recursively query the fonts (ttf, ps & otf) in the directories you give it to search, sort them quickly, (avoiding bugged or broken ones) and show them. Then, you can tag them, sub-tag, re-sort according various tags, preview... Even create a pdf Font Book...
Fontmatrix has been available to install from the Ubuntu universe repository since jaunty, and version 0.6.0+svn20100107-2ubuntu2 is currently in maverick and natty. A brief explanation about using fontmatrix is available on their website.
Also, there are lots of fonts available as software packages. Font packages are named in the form ttf-* or otf-*. It is better to install fonts as packages instead of manually if possible. You can use tools such as Synaptic, apt-get or the Ubuntu Software Centre. The Software Centre has a dedicated fonts section.
In addition to manually installing them inside
~.fonts (see bobince's answer) and FontMatrix (what nhandler shows you), there is also another font manager aptly named Font Manager (install Ubuntu package for 10.10, or download package for 10.04 and maybe older versions) that is quite lightweight (and has a Gtk GUI).
Another question, about installing Google Fonts, was closed as a duplicate of this one, though it isn't really (being rather narrow).
A better answer than the one provided there (i.e. to go to Google Fonts and look up the font and go through their weird downloading system) is to get it directly from Github, e.g.: Roboto Mono font files
The rest of them are available at https://github.com/google/fonts/tree/master/apache, and there's also a ZIP file of them available from the main https://github.com/google/fonts#readme page.
So, if you want to script this stuff (e.g. regularly download the latest version), you can do it with a Git checkout, or by using wget or curl to pull down the exact files you want.
PS: There's another duplicate question at "Downloading Google Fonts". It details some other methods, like using an installer script from googlecode.com and (for more than the Google Fonts) using tasksel.