xelatex template compile error: Charis SIL font not found

I tested xelatex for the first time with the TeXWorks template using fontspec, and I got a compile error as below:

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!
! fontspec error: "font-not-found"
!
! The font "Charis SIL" cannot be found.
!
! See the fontspec documentation for further information.
!
! For immediate help type H .
!...............................................

l.14 \setmainfont{Charis SIL}
% set the main body font (\textrm), assumes Ch...
? H
'''''''''''''''''''''''''''''''''''''''''''''''
A font might not be found for many reasons.
Check the spelling, where the font is installed etc. etc.
When in doubt, ask someone for help!
...............................................

The thing is that there actually exists "Charis SIL" font, but it's not installed in my Windows 7 or Ubuntu 10.04. Charis SIL font can be downloaded via : http://scripts.sil.org/cms/scripts/page.php?item_id=CharisSIL_download , and how to install can be found in : http://scripts.sil.org/cms/scripts/page.php?item_id=DecompressUtil

Xe(La)TeX & LuaTeX looked cool. I'll try more later.