Considering the purchase of a piano? The following sites will answer many of your questions.

      http://www.bluebookofpianos.com/american.htm

     http://www.concertpitchpiano.com/Piano_Types.html

      http://www.know-your-keyboard-piano.com/

       http://www.pianoworld.com/directory.htm

      

         http://www.pianoworld.com/directory.htm

The following sites contain tutorials on music theory, history, exercises, plus music scores and more.

      http://www.teoria.com/

     

      http://www.makingmusicfun.net/

      http://www.music-scores.com/