I took all of the tubing destined for pushrods (no, it is not anodized when
we receive it) and brought it to a shop to have it professionally alodined.  
You can find a local shop in your Yellow Pages.  This protects the inside of
the tube.

After I made it onto pushrods, I brought them to be powder coated.  I brought
mine to a local specialty bicycle factory (you won't find this in your town,
but you will find powder coating places in the Yellow Pages) and had them
powder coated white.

Powder coating is a little "over the top".  Probably any old paint will do,
though I admit that zinc chromate and epoxy based paints are probably better.
 Besides, you can see any corrosion that happens on the outside of a tube and
take care of it before it gets too bad.

I wouldn't worry about the inside of brake lines and hydraulic lines.  The
fluid inside will inhibit corrosion.  I will defer to Dan Schafer's advice
concerning the outside of the brake lines.  FWIW, Brent Regan shines his up
and paints them with clear Krylon.  I tried this on one fuel line, and it
looked nice, but then I decided that I wasn't building a show plane and
stopped doing this.  A Scotchbrite pad gave a nice brushed aluminum finish to
that line.

- Rob Wolf
LNC2 51%