If you don't live in New York or Los Angeles, it is often hard to find a label internship. However, when interning at a label you will be working in one specific department with only a few particular bands.
Distribution companies offer exposure to more artists' materials to interns than labels do.
One of the main functions of the distribution company is to sell records to record stores. This often means that internship positions involve a lot of mailroom, with no actual hands-on experience. You can learn basic sales and retail promotions with this type of internship. Independent marketing companies offer the best introduction to the music industry through an internship. Interns get to work on their own and call their own shots.