Blatantly ripped off of Marathon's Story is word of a new Marathon site aimed at Windows users, Orbital Arm. As Halo attracts more PC users to Bungie's flock, some may want to learn more about Marathon, which Halo appears to have very strong ties to.
The site is very well done, despite its limited scope (only Marathon 2: Durandal was released for Windows). If you're interested in playing this classic game on your PC, stop by and check it out. M2 may be dated compared to newer titles, but it remains a well done first person shooter with one of the most compelling storylines ever. Highly recommended.