LilyPond -> Midi?

[Aaron Morse]

Perhaps this is explained clearly elsewhere, but I have a question. I
have the following file compiling a score of a composition I just
wrote:

\include "horn.ly"
\include "trumpet.ly"
\include "drums.ly"
\include "bass-tbone.ly"
\header {
        title = "Ea"
        instrument = "Trumpet in C, Horn in F, Bass Trombone, Percussion"
        composer = "Aaron Morse"
}



<<
\new Staff \trumpet
\new Staff \horn
\new Staff \tbone
\new Staff \percussion
>>

How would I specify for it to create a midi sound file of the piece? 

My second question is what syntax I would use running the midi2ly if I
have a midi file I want to transfer to a lilypond file. I didn't find
anything about this in the documentation. . .

Thanks,
Aaron