One of my friends had the same question, and as stated above, you only need to download Client.zip, a launcher, and Launcher.dll from www.zloemu.org
He thought that we would need to download the crack BF3, but you don't. Once you extract the files from Client.zip into the Origin BF3 folder, it will replace some files like the Core folder, bf3.exe, etc
Once that is done, just place the launcher and launcher.dll in the BF3 folder and you will be able to play on ZLO servers.