There are a lot of useful English-learning and English-teaching materials on the website, such as BBC Website. 

It provides teachers with various teaching materials to use and students with practical materials to learn.

"Free English teaching and learning resources" is another useful and practical website for teachers and learners.

It is divided into 10 categories, including speaking, listening, reading, writing, grammar, business, vocabulary, pronunciation, TOFEL & TOEIC and idioms.

Students can choose the category that they have difficulty or interest in learning.

Most important of all, learners can choose the most suitable materials for themselves according to their levels.

For example, in speaking part, learners have 5 choices, such as low beginning, high beginning, low intermediate, high intermediate and advanced.

As a learner, s/he can choose one of the level and after s/he improves, s/he can learn the next upper level.

some useful links for teaching Grammar:

http://owl.english.purdue.edu/handouts/grammar/index.html

Sites for Listening

Sites for Reference

Powerpoint Weblinks