Puzzles, quizzes and games are helpful for learning a language and keeping the learning process interesting. Activities for ESL Students (a4esl.org) is one site that is designed to help students learn English using quizzes and puzzles with varying skill levels.
Speaking is a crucial part of learning a language. For students learning English, there may not be good opportunities to practice speaking with native English speakers. The Internet makes it possible to speak to others who are also learning or to native speakers for free using chat programs like Skype.com. While some sites charge for their services, MyLanguageExchange.com is a free site with over 1 million members.
Listening to a language being spoken helps the learning process. There are many online sites where a student can listen to English being spoken, sometimes in entertaining formats, such as movies or television shows. YouTube.com is a good free source where users can search for videos on a variety of subjects.
Reading is another important skill to develop. For an advanced student, online newspapers are a solid option. For new students, try looking for online children's books or online materials for children; the simple sentence structure and small vocabulary are good for beginners. The Baldwin Online Children's Project offers a variety of free classic children's books to read online.