Here are a few web sites I have found useful.
This list is just a start. Many offer free things, some offer a mix of free plus extras if you subscribe.
To practise aural work and theory topics
To listen to music:
Piano Technicians Guild - includes information on how pianos work, how to care for your piano
A wealth of information and resources for teachers, parents, students - everyone
Here is where you can listen to the Supersonics Pieces you may be learning. Just click on the album the piece is from and mp3 tracks will be available: