Known as the latest version of the new modloader, Forge Modloader 1.5.2 or FML 1.5.2 provides support for the textures that are in HD. This MOD is only compatible with textures at 128x and 256x resolution. At this moment OptiFine is needed for a better quality and for the future is announced that FML will do OptiFine job too. Until now this is the best mod loader on the marketplace. FML can be used without Minecraft Forge and it is compatible with Modloader based mods. Also it covers the main environments: client, server and bukkit because all environments share the main mod leading cod base.
Download the MOD and extract it;
Locate your minecraft folder and open minecraft.jar file;
Copy all your content from the downloaded mod into the minecraft.jar file;