Yes, you can just delete them, but I what I would recommend instead is that
you move them to another folder. I have one called Available Fonts, from
which I can install fonts as needed for specific projects. Obviously, a font
manager of some kind would be even better, but you can be your own font
manager if you don't have to do it often. To avoid deleting vital fonts, see
http://word.mvps.org/FAQs/Formatting/DeleteFontsSafely.htm, noting that this
is an old article and may not include some of the new fonts required for
Office 2007, nor does it mention the "Web-safe" fonts introduced by MS some
years back (Georgia, Verdana, etc.).

I believe that either the article is in error or you're possibly
misreading it. Windows XP only loads fonts as needed. HOWEVER - there
are some applications, notably most of Adobe's (Photoshop, InDesign,
Acrobat, etc.) that DO load all your installed fonts when they start,
and it is a royal pain!

A font *index* is a very tiny piece of the system registry, which does
get loaded into memory.

Hundreds of fonts are not a problem for XP or Vista. Thousands can
begin to get awkard. There were finite limitations in earlier systems
such as Windows 3.x and 9x/Me.

TT is Truetype, O can be either a Truetype-based Opentype font with a
.ttf extension or a font with an .otf extension. The upper-case "A" is
a font used only for on-screen display. A lower-case "a" would be a
Type 1 font.

Unwanted and unneeded fonts can be deleted. In general, unless you
know exactly where they came from and can find that source, they
should first be backed up or copied somewhere so you can retrieve them
easily.

A Font Manager such as Suitcase, Typograf, Printer's Apprentice, Font
Reserve, and many others will allow you to dynamically install and
uninstall defined groups of fonts as needed. For instance, if you have
a group of fonts that you use to make greeting cards that are unneeded
when you're composing the company annual report, and vice versa.

There are many lists of what fonts should not be deleted; NO TWO
AGREE! And to those, you'd have to add fonts that are used in
documents you create or read, and fonts that are needed by specific
applications you've installed. For instance, Turbo Tax installs fonts
needed to display and print tax forms, Corel Draw installs its
standard default text font, etc.

This article was written for Windows 98. Its general approach is
excellent, but the limitations and font list are obsolete:
http://graphicssoft.about.com/od/aboutgraphics/a/fontoverload_2.htm

This list is more current, and includes some that are not universally
needed:
http://styopkin.com/articles/fonts_installed_winxp.html

One thing that no list that I've found includes is a statement that
fonts that have the Hidden attribute should not be deleted. The most
notable one of these is "Marlett", which contains the symbols used for
 such things as the up and down arrows in scroll-bars and the
maximize/minimize/close buttons in a window!

Hope this helps

 - Character