Download TextureUnstitcher

Field release of Minecraft 1.6.1 has become a topical issue of the conversion of the old texturepack in resurface and back. So the game developers have created a simple utility called Texture Unstitcher, which allows you to implement it, it is enough to specify the path to the archive resurspaka and the program will automatically generate texture pack compatible with older versions of Minecraft

Details on the conversion of the textures in the resources and back, you can read here