you can DIY your PC into a music studio. Do it as follow: use this USB MIDI cable to an electronic musical instrument and your computer, then you'll be able to play songs at same time your PC will record this song! Some time you can overdub additional instruments, then edit, mix and even print sheet music of your final compositions with appropriate software.
Description:
 USB MIDI Cable
Model: 
 SA-U1019
Features:
 1.Plug-and-Play.
2 1-in/2-out MIDI interface
3. 16 MIDI input channels/16 MIDI output channels
4. MIDI activity indicators for each port
5. Usb bus powered; Requires no external power
6. Extremely compact and lightweight
7. Cable Length: 1.8～3. 0 m
Technical Details
Supports: Windows Vista/XP and Mac OS X
Turn your PC into a music studio by connecting a music keyboard to your computer with the USB MIDI cable
Easy to install with built-in driver; USB powered, no AC adapter needed
1 in + 1 out MIDI interface; 16 MIDI input channels & 16 MIDI output channels
LED power indicator; MIDI in & out signal indicator; Supports: Windows Vista/XP and Mac OS X