OK here is the tranlation from bokmeow :
Woodbass:
Way to hold the Neo Geo Pocket Color-
Lay it on its side (button on top and lever on bottom), control the lever with the left hand and buttons with the right.
Way to play-
Up and down lever motions select 2 chords, A and B buttons play the instrument. Play the four different chord combinations (Up/down lever + A buton, or Up/down lever + B button) while reading the rhythm gauge.
Play-
Left rhythm is played with the A button, right rhythm is played with the B button.
Chord A- Lever up*
Chord B- Lever down*
*Because the directions for the Neo Geo Pocket Color are changed to that shown in the picture on the upper right, please take note and realign your orientation.
Sax:
The way to hold the Neo Geo Pocket Color- Put the Neo Geo Pocket Color on its side, Lever on top and buttons on bottom. Left Hand will control the lever, and right hand controls the buttons.
How to play-4 scales A/B/C/D is performed by a combination of lever and buttons. While reading the rhythm gauge, enter the correct rhythm with lever and buttons. A combination of Lever and Buttons entered at the same time is possible. However, Scale A and B cannot be entered at the same time.
Scale A: Lever Up
Scale B: Lever Down
Scale C: A button
Scale D: B button
Blues Harp:
How to hold the NGPC-hold it as you normally would, upright, right hand on the right side, left hand on the left lever.
How to play-Control the 'casoul' and combination of of blowing and sucking to play. A button is for blowing, B is for sucking. While reading the rhythm gauge, move the lever to the 'casoul' indicated by the marker, and enter the correct intake or expulsion of breath with the buttons.
Casoul:left/right
Blow (expulsion): A button
Suck (intake): B button
Scratch:
How to hold the NGPC-hold it upside down, right hand on the lever and left hand on the buttons.
How to play-A and B buttons select the chords, lever controls the scratch to play music. Once the rhythm gauge starts to move, follow the guide marker and hit the appropiate buttons, when the flash marker reaches the correct timing, do a half rotation (180 degrees) on the lever.
Violin:
How to hold the NGPC-
Stand the NGPC on its side (lever on top, buttons on bottom. Left hand controls the lever, right hand controls the buttons.
How to play-A special power guage and an extend gauge is used for the performance. Storing power in the power gauge, and then using A or B button to play the strings is the fundamental of performing. While not playing, rotating the lever will store power, and once you play the string the gauge will decrease. When the extend gauge happens, before the gauge draings, you should continue holding down the buttons.
Playing the A string: A button
Playing the B string: B button
Power gauge (center top): rotate the lever
Extend gauge (bottom right): before the extend gauge drains, continue holding down/ pressing the button.
Trumpet:
How to hold the NGPC- stand it on its side, buttons on top and lever on bottom. The right hand controls the buttons, left hand controls the lever.
How to play-
Special breath gauge will be used for this performance. Store your breath in the breath gauge, and play A/B/C/D four different scales with a combination of lever and buttons. While you aren't playing anything, rotating the lever will store the breath gauge, and playing will decrease it. While reading the rhythm gauge, use a combination of lever and buttons to play. Again, you can press many combinations of lever and buttons together. But, the scale C and scale D cannot be played at the same time.
Scale A: B button
Scale B: A button
Scale C: Right lever
Scale D: Left lever
Breath gauge: rotate the lever.
By the way, thanx a lot for this bokmeow, I'm now better at this game
but a real faq would be nice, 'cos the RPG (Joinas)-mode is a bit difficult without understanding what the people say, especially I don't understand the shops very_ang
But nevermind that, COOL game COOL idea, so let's JAM
you can find the zip file <a href="http://www.angelfire.com/rnb/ngpcland/ccj.zip" target="_blank">HERE</a>. Would be nice if you translate some of them ... especially the trumpet+cello 
