I keep hearing about VBA and Excel macros.
What is the best way to learn VBA and macro writing?

I am an experienced C and Unix systems programmer, so
I do not need to learn "how to program". I just need
to learn the language and perhaps some common techniques
that might be specific to the VBA programming environment.

If the answer to my question is "RTFM", I would
appreciate pointers to the "FM". Also, I'm sure there
are a multitude of books on the subject, ranging from
bad to worse. I would appreciate recommendations for
the exceptional one or two books.