This project includes various .NET-based tools for working with Minecraft, including a speedy map renderer and an easy-to-use mod installer.
MTS is a fast Minecraft map renderer, capable of processing extremely large maps with an efficient caching system. It supports a variety of modes, and can load both singleplayer and multiplayer worlds. It also includes a command-line interface.
Minecraft Mod Installer is a program that automates installing Minecraft graphics packs and mods. It can intelligently install mods from zip files without any user interaction, and create and restore backups of your Minecraft executable so you can use mods temporarily or roll back ones that you don't like. (You don't need this program to install texture packs that support Minecraft's new texture packs menu, but it will still work.)