BBC Learning English (UK)
Levels: Pre-Intermediate, Intermediate, Upper-Intermediate, Towards Advanced
Contents: each level has 30 units, each unit with 5 sessions with various activities (listening, quizzes, matching, etc.) plus vocabulary and grammar reference section
No registration required
USA Learns (US)
Levels: Beginner, Intermediate
Contents: each level has 20 units, each unit with a variety of activities, all skills
Registration required (free), the system keeps track of your progress
Let's Learn English (VOA) (US)
Levels: Beginner, Intermediate
Contents: each level has 52 weekly video lessons with listening, speaking, pronuncation, writing, learning strategies and quizzes
No registration required
