Some useful websites:
http://www.english-online.org.uk/index.html
http://www.english-online.org.uk/elem2/elem2_1.htm
http://conversa1.com/grammarseries.htm
http://www.english-online.org.uk/course.htm
http://www.edufind.com/english/grammar/present_simple.php
http://esl.about.com/od/businessspeakingskills/a/t_vocab.htm
http://www.testyourenglish.net/english-online/subjects/prescont.html
http://www.testyourenglish.net/english-online/subjects/spresent.html
http://www.lingua.co.uk/english_grammar_guide.html

There is plenty of grammar and you'll also find some interractive lessons. Enjoy