Is it possible to play sheet-music through an on-screen piano?

Hello

In what copious free-time I have, I thought it'd be a good idea to learn to play Piano.

I have some Tom Lehrer sheet-music which I'd like to utilise on the computer, with some 'learn to play on-screen' type setup.

Do you know of any, preferably free, softwares which have this facility?

Thanks in advance, for any recommendations,

Chip D. Panarchy