All the sierra adventure game soundtracks are available at Quest Studios.
http://www.queststudios.com/
(Includes King's Quest, Space Quest, Quest for Glory and many more!)

Priceless. Thx.

Jets'n'Guns OST by Machinae Supremacy
http://www.machinaesupremacy.com/jetsnguns.php

Outcast was on my list but the website isn't working for me. Does it work for you ? Maybe there is a regional restriction ?

Yeah works fine.
Edit: this is a an alternate fansite link

Thx. I did put this one. If anybody is having troubles, let me know. Awesome musics btw. It's a "must have" soundtrack.

Great Post!

Added Obscure 1&2, and Hitman to the list.

Wow, Outcast's website is still online!
I'm in France too, and the website is working fine for me.
Oh, and you should also add this link (on the LucasArts soundtracks website) for Grim Fandango as they have an additionnal soundtrack (a complete rip of the game's music I believe).
EDIT: Indiana Jones and the Staff of Kings on the official site of the composer Gordy Haab. And you can listen Ray Harman's score for the same game.

I'm not. ;) Hopefully those links are working for everybody.

Hey thanks man!

You're welcome ass... I mean Filthhealer.

Star Wars: The Force Unleashed official promo soundtrack available for free listening (and download for those who know how to) on Tracksound. Very nice soundtrack by the way ;)

Updates : Indiana Jones and the staff of kings, S.T.A.L.K.E.R shadow of Chernobyl, a bunch of Tom Clancy's, the incredible Hulk, Lineage 2, Arcane online, Clive Barker's undying, return to castle Wolfenstein and Trespasser : the lost world. All from composer's websites.
Edit : Splosion man (with the donut song!) + System shock 2.