Complete documentation over here. CraftBukkit/Spigot server versions over here.
This is a Minecraft Mod that allow you to compress and uncompress some blocks like Stone, Cobblestone, Wood, Sand, SoulSand, Gravel, Dirt and Netherrack. Get this mod and you're gonna spare a lot of space !

This mod works in single and multiplayer (with server), equipped with Forge. So, make sure to install it first. Since the 1.2, it is also compatible with other mod like ExtraUtils 2.
If there is a problem, see this page for compatibility details between versions.
This mod is currently available for:
The previous versions and the changelogs are available on the mod website.
Simply put the .jar mod file into the "mods" directory of you minecraft client folder, or server folder.
First, here is the list of the blocks that you can compress (and uncompress):
Get a crafting table and do like on this picture. You can naturally do these crafts with all the blocks listed above.

All compressed blocks can be placed in the world. But, once you destroy them, you don't get back a compressed block. You got a stack of the uncompressed blocks. For example: if you destroy a compressed Cobblestone block, a stack of 4 ~ 7 Cobblestone drop. Like on this picture:

And since version 1.2, once you destroy a compressed Stone, it drop a stack of Cobblestone (instead of a stack of stone before).
The compressed Sand and Soul Sand that fall, the Stone that drop Cobblestone, and the list of many others behaviors featured in this mod are available on the Behaviors page.

Just post a message on the issues page. All the doc of previous versions is available over here.
No files available for download.