This is a great website with lots of examples and explanations. They also provide visuals which are very helpful. Another bonus is that they have practice exercises.
English Grammar Online
This website is good at breaking down when to use the different verb tenses. They also have some simple exercises that you can use to practice your grammar skills.
Randall's ESL Cyber Listening Lab
Practice your listening skills using any of the difficult or advance level recordings. Make sure to do the activities that go along with the recordings.