About.com Beginning English - 8 basic lessons.
engVid.com - hundreds of free English video learning lessons from native speaker teachers.
Free Online English Courses from a partnership between ALISON & the British Council. Many advanced modules are available.
Dave's ESL Cafe - Materials for teachers and students alike. For students, there are extensive grammar lessons, materials on phrasal verbs, idioms, quizzes, slang, and online forums for help and discussion.
ESLPod - this website offers literally hundreds of podcasts. The site is run by "a team of experienced English as a Second Language professors with over 30 years of high school, adult, and university ESL teaching experience." Learning guides with sample sentences and cultural notes are provided with each current podcast. The topics of the podcasts include relationships, business, travel, daily life, and more.
The English We Speak (BBC) - three-minute podcasts on everday (British) English phrases and slang.
English Teacher John Show Podcast - these ten-minute lessons focus on clear pronunciation. Full transcripts are available. Ideal for intermediate students.
Listen to English - Short monologues on various topics.