Activities for ESL Students - This website has useful information for all levels. It includes quizzes on grammar and vocabulary, listening and pronunciation practice, and VOA audio podcasts. It also has crossword puzzles and over 40 quizzes in bilingual languages.
Interesting Things for ESL Students - This website is full of exercises in grammar, pronunciation, listening, spelling, and vocabulary development for different levels. One heading lists “Easy Things for Beginners.” Other activities and exercises are not specified by levels but are generally intermediate.
English Grammar - Help with rules of grammar.
5 Minute English - Designed to give short and easy explanations and exercises for English as a Second Language Learners.
Dave's ESL Cafe - A collection of lessons and resources on all aspects of grammar. They give explanations and usage examples.
English Club - A free website for English learners. They provide help and tutorials on everything from tenses to prepositions.