Never mind, it turns out that Yamaha still has the songpacks up on their website.
Here's the link for anyone interested: http://www.yamahamusicsoft.com/index...ategory_id=191
(They cost money, though, which I didn't realize before. $15 for a pack of 4 songs for a game I rarely play...)
No clue. I wouldn't have gotten it if my mom didn't want to get my little brother a new keyboard for Christmas a couple years ago. I told her to get that one because it came with Keyboardmania.
And now I never play it because it's TOO DAMN HARD.