Open University Distance Learning
The Open University is the largest university ion the UK with over 250,000 students currently registered and 11,700 staff. It was set up in by the government in 1969 to provide wider access to university education. It has a very good reputation.
In addition to degree level courses (which cost money, but are very good value) they offer introductory courses for free through the Openlearn programme. ( http://openlearn.open.ac.uk/)
The OpenLearn website gives free access to Open University course materials. This is the LearningSpace, where you'll find hundreds of free study units, each with a discussion forum. Study independently at your own pace or join a group and use the free learning tools to work with others. If you like the approach, they obviously hope you'll sign up for an OU degree later on.
Some, but not all OU degree course are supported worldwide others only in Europe.
Meanwhile I believe Openlearn is freely available anywhere. Subjects covered are:
Arts and Humanities
Business and Management
Childhood and Youth
Computing and ICT
Education
Engineering and Technology
Environment, Development and International Studies
Health and Social Care
Law
Languages
Mathematics and Statistics
Psychology
Science
Skills
Social Science