What you are looking for is
mod rewrite. requires an .htaccess file with the correct settings and a server capable of handling it e.g. running Apache. it has nothing to do with Dreamweaver or any other editor.
the .htaccess will look something like this:
Code:
#DirectoryIndex index.php index.html
#Options +FollowSymLinks
#Options -Indexes
<IfModule mod_rewrite.c>
RewriteEngine On
#RewriteBase /relative/web/path/
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^(.+) - [PT,L]
RewriteRule ^(.*) index.php
RewriteCond %{HTTP:Authorization} !^$
RewriteRule .* - [E=REMOTE_USER:%{HTTP:Authorization}]
</IfModule>
#php_value register_globals 0
alternately you could make separate directories and have an index.
html,
php whatever in them and kind of fake it, but its not quite the same.