There are several types of companies that produce self-learning materials for learning languages. I ran across a series of videos by Professor Arguelles that describes some of these series of self-learning materials, for example Assimil. These reviews are interesting in that they can help in deciding what materials to use when starting to learn a language.
Here is the series of Youtube videos:
Spoken Language Services
Central Institute of Indian Languages
L’Harmattan et L’Asiatheque