The "corefonts" package makes installing Windows fonts like Verdana on Linux systems easy. However, the corefonts ebuild does not include Tahoma, the font used in Windows XP buttons, menus, and dialogs. As a result, I decided to install them manually.

The fonts will not be recognized unless special files exist in the directory. To make these files, type the following commands:
ttmkfdir -o fonts.scale
mkfontdir

You need to add the directory where the fonts are stored to /etc/X11/xorg.conf (if you are using XFree, then you should edit XF86Config):
Section "Files"
...
FontPath "/usr/lib/win32/fonts/"

Next, open up /etc/X11/fs/config:
catalogue = /usr/share/fonts/75dpi,
...
/usr/share/fonts/ttf/western,
/usr/lib/win32/fonts

Also edit /etc/fonts/local.conf:
<fontconfig>
<dir>/usr/lib/win32/fonts</dir>
</fontconfig>

Finally, restart the font server.
/etc/init.d/xfs restart
The fonts should appear automatically.

References:
Installing fonts in Linux and Mozilla
Internationalization How-to (Gentoo)