If you have the SPCs of that ports then NintSPC is the easy way for you. Converting to Addmusic4 (reminds me I wanted to write a tutorial how to convert from AddmusicM to Addmusic4 *gasp*) shouldn't be too hard at all. Then again, people say that pitch slide commands are different..
gocha made also a very smilar Tool to nintSPC, which is called "smwmusicrip". It can be fpund in one of the Japanese Music Packs hosted on BlackYoshi's Website. Just search Black Yoshi's Website at Google since I'm too lazy.