There is no support for servers, please use Bukkit.
Any operating system that supports Java 1.7+
Easy download of patches
Additional instructions for manual way:
1. Download the Patches.zip here.
2. Choose your patch, each patch file will be named 'minecraft.patch' and will be placed in folders, the first letter of each folder represents the type of Minecraft revision (a = alpha, b = beta, f = full/final).
3. Copy the 'minecraft.patch' file to the same directory as MC Downgrader is located.
4. Run MC Downgrader and just click patch.
You can download it here.
The tutorial can be found here.
The download can be found here.
Choose which patch you want from here.
This tool is hosted on the FFMC server, servers cost money to run. If you like the tool please feel free to donate!
I share the same viewpoint as CyborgDragon.
This modifies the minecraft.jar binary file. By downloading and using this tool you understand the risks of damaging your minecraft.jar file and that 68x will not be held accountable for your actions!
Boring Copyright stuff
This mod (plugin, a patch to Minecraft source and guides, henceforth "Mod" or "The Mod"), by the terms of [url="http://www.minecraft.net/copyright.jsp"]http://www.minecraft.net/copyright.jsp[/url] is sole property of the Mod author (68x, henceforth "Owner" or "The Owner"). By default it may only be distributed on minecraftforums.net, fatalfatalis.ca, bukkit.org. It may only be mirrored or reposted with advance written permission of the Owner. Electronic Mail is fine if you wait for a response. URL shorteners or other attempts to make money off The Owner's Mod are strictly forbidden without advance written permission.