Mambo is an open-source content management system (CMS). The members of the Mambo core development team forked the project and created Joomla!. Joomla! 1.0 was essentially the same codebase as Mambo 126.96.36.199, but current versions of Mambo and Joomla! are significantly different.
Mambo is easy to install on DreamHost through its intuitive web-based interface. If, however, you need a more automated installation process, there are hundreds of other hosts who offer such service via the Fantastico installer or another automated process.