Basically, it adds all the new items into the game. The .esm's actually add, and the .tar.gz (double packed) are the art files.
Map 1 will be questable in a month. It should be a few months after that before an alpha.
However, we have a project for the Oblivion CS (besides Hammerfell) that was supposed to be released soon. However, we lost the entire landmass the other night.

We still have the Heightmaps, and we're seeing how much we can save.
Right now, however, The continent is built (exterior). I have alpha's on my comp, and I can wander around at will. There are even NPC's on a few of the maps ([url="http://tamriel-rebuilt.org/?p=modding_data/maps"]http://tamriel-rebuilt.org/?p=modding_data/maps[/url])
Our biggest challenges are the way they built the OoT, because older mods that were built on early OoT versions need to have a lot of things replaced.

Also, we are working a way around a major bottleneck in reviewing.
However, with Oblivions tools, Hammerfell should go much faster than Morrowind.
[url=tamriel-rebuilt.org]Tamriel Rebuilt and,[/url] [url="http://z13.invisionfree.com/Chus_Mod_Forum/index.php?"]My Mod Fansite[/url]
I am the Lord of Programming, and your Mother Board, and your RAR Unpacker, and Your Runtime Engine, can tell you all about it