The Milkshape_3D_1.8.0_Setup.exe file you have requested: Tools and Utilities / Modding Tools / Milkshape 3D v1.8.0 - 5.34mb is not available. Perhaps try browsing all files for the game Halo: Combat Evolved and upload any files you want to share or are missing. This is the only information we could locate:
A 30 day trial for ms3d. This is a modeler program that lets you create and edit models for halo.