The Common Object Request Broker Architecture is a specification for creating, distributing, and managing distributed program objects across a network. Both the International Organization for Standardization and X/Open have sanctioned CORBA as the standard middleware architecture for distributed objects. CORBA was specifically designed to support heterogeneous environments, different vendors' products, and several popular programming languages. MICO is an OSS implementation of CORBA. Inspired by the GNU project, the name "MICO" stands for "MICO Is CORBA". MICO has evolved into a mature open source project, with close to a half million lines of source code contributed by more than 150 programmers. The author discusses MICO's internal architecture and then offers a few guidelines to choose the right CORBA implementation for your purposes.