Hello,

The black keys are the sharps (notated with a #) or flats (notated with a symbol that looks like a "b") that come between some of the letter notes. For instance, the black key above C is the half-step between C and D, and is notated as C# or Db, depending on the key signature of the music.

Actually, if you're using Composer, you can write the sheet music as if it were all on the white keys (key of C), then transpose the pitches to another key (with sharps/flats, "the black keys") for another musician.

For some good info and exercises, you can try out http://www.teoria.com/index.html

I'm sure there are other folks here who can explain things much more thoroughly and expertly than myself, as I am mostly a bass and guitar hack ;)

ttfn,
Sherry