#2
if you have something to convert the midi from the keyboard to the computer usb. i believe you can get the M-audio uno or you can get an audio interface that has midi I/O and connect it that way
#3
Yes. According to the specs there is MIDI out. So run a cable from your MIDI out to your soundcard's MIDI in.
#4
Just remember your options get cut down with budget Keyboards.
I was once heavily prominent on these forums from 2004-2007, let's see how long I can stay now that I'm back.