Yes this is a good site, and it is actually a sort of revision and test for:http://www.understandquran.com/
I agree that grammar is important, and the site I have given above teaches it in a novel and simple way. I learnt a great deal by their short course, and then I studied the Basic course on my own. It is just my age and lack of commitment that has thrown me back to square one, but the method is very good indeed.
Another method is by using alaamaat - identifiers: using 3 colors, but it is presently only in Urdu:http://bait-ul-quran.org/
and of course, one now given by our new sister ashg1989 is good, too: It also uses three colors.http://arabic.speak7.com/index.htm