Following are some recommended sites:

1.This is for calculating chords in major and minor keys!
http://www.musictheory.net/utilities/html/id95_en.html

2. You can practice naming notes! Treble, bass and C clefs!!
http://www.musictheory.net/trainers/html/id82_en.html

3. Look at this web site also:
http://www.emusictheory.com/practice.html

4.Star Wars
A capella tribute to Star Wars and the music of John Williams!!
This is really cute!!
http://www.youtube.com/watch?v=lk5_OSsawz4