MosForge.net (MF) is Mambo's official home...aside from
mamboserver.com. At MF you will find the official documentation and many of the components, modules and templates (CMTs) available for Mambo. They are not all there, but the ones that are, are the most current versions. There are also several "fan" and mambo news sites that offer CMT downloads, such as
mamboportal.com.
Add-ons often involve modifying Mambo's core files. To do this, you will need ftp access to the directory Mambo is installed in. If you have access, but do not wish to make core file modifications without assistance, I'm sure you will have no problem finding some one here that will be willing to help you. Happy Mamboing!