Hi Emanuela

I am currently studying with the Open University, which has pioneered distance learning very successfully, to the point where it is now the UKs largest university.

Through some 40 years of development, they have put together some top quality materials and processes across an extraordinary range of subjects, and are ranked amongst the best educational institutions in the UK by the official assessments.

They seem to be offering quite a lot of web-based stuff now as well, and students are certainly based all over the world. This might be a starting point if you want to check it out:

http://www3.open.ac.uk/learners-guide/

or as Google gives it:

The Open University, the UK's largest university for part-time higher education,
offering among the world's best distance education materials for undergraduate ...
Open and distance learning. Study methods, courses, teaching, knowledge media, research.

http://www.open.ac.uk/frames.html