This websites are totally free and there are no pop-ups or viruses etc.

http://www.sheetor.com/

http://www.pianofiles.com/

http://www.writtenmelodies.com/

http://my-piano.blogspot.com/

http://pianotte.szm.com/

http://fsm3000.thatsjustme.net/sheets.ph...

http://www.mx-music.com/

http://www.tapartoche.com/

http://pianomusicsheet.blogspot.com/

http://www.themusicblogger.com/

http://www.thepianocian.com/

http://words3music.100free.com/

Hope this list helps.
References :

It has only got three musicals though – The Phantom of the Opera, Les Miserables, and Cats.

Edit: Oops! Cats is only coming soon but the other two are there.
References :
http://cloud.prohosting.com/hindec/indexle.htm