How much time do I need to spend on console programming before getting into Windows?

- or to put it another way -

What skill set is necessary to begin Windows programming?

I've been working at this on my own in my 'spare time' for a while now but I'd really like
to start working with MIDI on some musical applications. It seems like that requires some understanding of Windows programming and the 'MIDI API' whatever that is. (Already got the link, thank you - )

I've got the Petzold book across the room waiting for me - how much dues do I have to pay? How long do I have to stare at the black rectangle??

-JM