Downgrading Minecraft Made Simple

When you have accidently updated to the latest version of Minecraft and you don't even have a backup of the old version and you really wish to play the old Minecraft version. you will need to downgrade Minecraft, Unfortunately downgrading Minecraft can be a little frustrating! but is not so hard to do, you can visit our Minecraft Downgrade Tutorial page for some usefull and updated info.

This tool might also help you in the downgrading process.

MC Downgrader - The Time Machine for Minecraft!

Features:

• Easy Download and Install of Python
• Easy download of patches
• Simple Patch/Unpatch
• Backups

http://fatalfatalis.ca/showthread.php?68-Downgrade-Tool
http://forums.bukkit.org/threads/tool-minecraft-downgrade-tool.13873/
Click here to Download
Tutorial:

This link might help too.
Minecraft Single Player Codes

Another tool to downgrade Minecraft.
MCPatcher

Easy up and downgrade your Minecraft
http://mojangcommunity.net/thread-448.html
http://www.minecraftforum.net/topic/352333-minecraft-version-patcher-mcpatcher-185-indev-mc-19pre4-15000-dls/
Click here to Download
Tutorial: