I have a <a href="http://www.casio.com/products/archive/Musical_Instruments/Standard/CTK-551/">casio keyboard.</a> And have had it for a while (a bout 4 years). But in the past couple of years i have gotten really involved in using Garageband and record daily on it. I have just realised that my keyboard has a MIDI in and out. My friend (a garageband user also) has an M-audio MIDI keyboard that links with Garageband and allows him to record software instruments on this little keyboard of his. I was wondering what i would have to buy to be able to this with my keyboard? Thanks if you can help.