music notation fonts

[Keith]

I'm very glad to see such a large open-source effort for music notation.  I've
actually started working on a similar project myself, although my intent is to
make a GUI-based notation application (along the lines of Finale or Encore)
rather than a batch system.

As I'm starting to learn about notation software, I've observed that most (if
not all) applications rely on music notation fonts to plot the notes on the
staff, and in many cases, the staffs themselves are part of the font.  So my
question is this: are there any truly open-source music notation fonts that I
could use in my application?

Assuming that I one day finish my project, I'd like to distribute it freely and
contribute it to the open-source community, but I don't know much about how
licensing works when you add third-party components, even if such components are
themselves open-source.  I'd appreciate if someone could shed some light here --
thanks!