A friend of mine is in a band whose members are scattered across the country. They all write songs that they need to convey to each of the others. They'd like to find some software that will not only allow them to input the tunes via keyboard and mouse onto sheet music, but also play said tunes (for those who can't read music). The basic requirements they are looking for are:

For Windows (tho if it also comes in Mac would be a plus)
Has to allow at least two part songs (four part would be better)
Note lengths in the Harmony part need to be able to be different from the note length in the melody line.
Has to be able to input from keyboard and mouse.
Must be able to play the song (to learn it by ear)
Must be able to print the songs.
Has to be $400 or less

Can anyone recommend anything, or point me to where I might find something?