Can any one give me a site where I can study how to efficiently play a piano online?
Try http://www.musiceducationexpress.com that offers printable (PDF) piano lessons. You can visit http://www.musiceducationexpress.com/Piano_Lessons.html to see a list of the topics covered by the lessons or you can download a complete piano course from: http://www.musiceducationexpress.com/Piano_Course.html
Free piano lessons are available at: http://www.musiceducationexpress.com/Piano_Lesson_1.html and http://www.musiceducationexpress.com/Piano_Lesson_8.html
Hope this will help.