Dr Ledgard's OOP Site - Contains an introduction to object oriented programming concepts based with examples in C++. Also includes a glossary, interactive quizzes and references. - http://www.eecs.utoledo.edu/~ledgard/oop/mainpage.html
Object Mentor Inc. - Provides training to object oriented developers looking to accelerate development with methodologies such as XP and advanced software design principles. Site provides articles, download, and courses information. - http://www.objectmentor.com/
Object Discovery Corporation - provides public courses and on-site training in C++, CORBA, Java, Enterprise JavaBeans, OOAD, UML and Object Oriented Business Process Reengineering. - http://www.objectdiscovery.com/