somkun:
How do I implement (physically) a mini-usb port so my keyboard can be plugged in and used (recive power and send keyboard signals)? I know that the Leonardo has a mini-usb already attached, can I just use that? if not, do I need to reroute power from the usb port to the power port on the uno?
If you go to the main reference page on the Arduino site there is a link to Keyboard and Mouse for the Leonardo.
http://arduino.cc/en/Reference/MouseKeyboard
This tells you a bit about using your Leonardo as a USB keyboard. I haven't read any of it but it may give you enough information on using the Keyboard library.