I downloaded appscript and it is unzipped.  I started up terminal and
changed directories to the folder rb-appscript-0.5.3 and I think that
I need to do the following three commands to get it installed:

ruby extconf.rb
make
sudo make install

after typing "ruby extconf.rb", I get an error message saying "can't
find header files for ruby."

The documentation said something about "Please note that the version
of Ruby included with Mac OS X 10.4 (Tiger) is missing the header
files needed to build appscript on PPC-based Macs."

I am not very experienced with doing anything at the command prompt,
and I am starting to learn Ruby.  I don't want to have to install a
new version of ruby.  I probably will mess things up even more.  I
also don't want to pay $200 to upgrade to OSX 10.5 which is the
highest version of OSX that a Power PC can run.  Is there any simple
way to get the header files (whatever they are ??) set up so that the
extconf.rb will work?