How I can install Emerald on 12.10?

I had to manually compile it from the last sources I found, since I wasn't able to find any deb with a newer version of it.

First, you need to install the dependencies:

sudo apt-get install git autoconf libtool libwnck1.0-cil-dev libwnck-dev intltool libdecoration0-dev

Download the package:

http://cgit.compiz.org/fusion/decorators/emerald/snapshot/emerald-0.9.5.tar.gz

Uncompress it and compile with these commands:

cd emerald-0.9.5

./autogen.sh && make clean && make distclean && ./configure --prefix=/usr && make && sudo make install

sudo chmod +x /usr/bin/emerald

To run it, simply execute:

emerald --replace

If it works, you can set this last command in the "Window Decorations" section in compiz configuration with ccsm.