I apologize if someone has already posted the bellow-noted listing somewhere else.
On the Yahoo Movies discussion list under "Silent Hill" (Go to Yahoo>Movies>Silent Hill>Message Board, for those unfamiliar with Yahoo - and get yourself a warm feeling when you compare the level of discussion here with theirs!
), the intro post under the topic "For those who want the songs from the movie", there's a list of 23 songs and which game they come from, as well as a URL where the poster, "potbellyraccoon", states that they can be downloaded, though I haven't tried his link. I checked the list against my own impressions and I think he's essentially correct.
(I didn't link directly to his post, as some BBs I've been on have had rules against linking to other forums so I never do at a new one until I'm sure of forum rules and unstated local customs.
The game music is available on CD, for those who are still looking for that. An outfit called "Import King" has been selling them on Amazon.