Disklavier

Hi
I've just invested in a mark II - mainly for my children to learn to 
play on, although I do want to use it for the occasional party etc.

I am searching, without much sucess, for easy to use midi files.  
When I say easy to use, as I am new to Midi, I am not yet familiar 
of how to properly manipulate the files when the right channels are 
not used for the piano.

The genres I am looking for:
- Rock and Roll
- Rythmn and blues
- Soul
- Boogie
- Contemporary rock.

any help would be much appreciated.

ps I also have the added CD player - can any one recommend a website 
that sells reasonably priced CDs. Yamaha is pretty expensive.