If you have a Windows installation, installing your Windows fonts is quite easy. First, create a directory to hold the fonts in your own home directory (you should be logged in as a regular user, not root, when you create this directory to ensure that you “own” it).
mkdir ~/.fonts (note the dot, which will make the directory a hidden one, and the fact that this directory must be named exactly as shown!)
Now, all you have to do is copy whatever fonts you want to use into that folder. For instance, locate your Windows installation's Fonts folder and:
cp *.ttf ~/.fonts/ (the ~ is a shortcut for specifying the current user's home directory, such as /home/foo; if you're working as root ~ refers to root's home, which is /root; note that your prompt ends with $ when you're a simple user, and changes to # when you become root)
Note that it may be necessary to become root to access the Windows partition the fonts are stored on. In that case, copy the fonts to your .fonts directory as root (substituting ~ in the pathname with the actual pathname, since ~ now points to root's home, not your own). Once the fonts are copied they'll be owned by root, which isn't what we want. To change this, issue the command chown -R user:user /home/user/.fonts/* where user is your regular login name.
After restarting the X server, KDE will see the fonts and KDE and its apps (such as KOffice and Konqueror) will be able to use the fonts without any further intervention on your part. On a side note, if you haven't used the latest incarnation of KOffice, you should definitely check it out. Version 1.2 is an impressive update to a solid set of tools. Aside from standard KDE applications, the fonts will also be accessible as options in KDE Control Center -> Look And Feel -> Fonts. AbiWord, by default, will not see the new fonts. I have not investigated a workaround for this (or even whether it affects all other GTK apps). AbiWord suffers from an apparently obscure bug on my machine (in several distributions and across several minor versions of AbiWord) which renders it unusable and for which I haven't been able to find a workaround.
If you don't have a Windows installation available, you can find the Microsoft core fonts (used in many web pages) on Sourceforge. The installation procedure is nontrivial but not difficult and is outlined clearly on the download page.
Unfortunately, OpenOffice.org also won't see the new fonts without a bit of intervention. Fortunately, OO.o includes an excellent utility that will have you up and running with the new fonts in no time. If you haven't yet fired up the version of OO.o included with Pscyhe, what are you waiting for? You'll be in for a pleasant surprise. The horrible, jagged font rendering of the past is gone. Even the user interface font is nicely rendered. It seems OpenOffice.org's last usability barrier (at least for me) has finally been lifted. It's not that I'm extremely picky, just that I use my laptop for most of my word processing chores, and LCD screens tend to exacerbate even slight font problems. All that being said, the greatest font rendering in the world is useless without fonts to render, so let's fix that. Open a terminal and become root user. From there, issue the command:
a short wait, the OpenOffice.org administration tool should pop up on
your desktop. At the bottom of the dialog, click on the button
labeled "Fonts ..." and point the resulting dialog to the
.fonts directory beneath your home directory. A few more
clicks and you should be able to fire up Writer and have all your new
fonts available. This tool can also be accessed via the system menus
under Office -> OpenOffice.org Printer Setup. Note that the
first method (as root) makes the fonts available to all users.
Starting it as a regular user will only make the fonts available to
that single user.