I was led to a blog that posts download links to various Ennio Morricone scores. I'm sure many of these aren't exactly legal, but a lot of them are rare or out of print.
Unfortunately the site that hosts mosts of the files only allows one download an hour or so, unless you want to pay a fee.
A couple I've downloaded so far that I'd recommend are
The Island and
E Per Tetto Un Cielo Di Stelle.
http://my.opera.com/Morricone%20lover/blog/Oh, and many of the titles are in Italian so if there's something you're looking for you may need to look up the Italian name.