outdoor mural

[michellyaqua12.livejournal.com]

my boyfriend's mom has asked me to paint a mural on a wall of their house (outside). i believe the wall is wood. i need to know:

1) what type of paint would be best for this? i am going to be doing a light blue over the entire area as a background to work with, and then for the rest of the mural i'll be working pretty small (she wants a picket fence with flowers, butterflies, etc). so i need something that i can easily cover a large area with (i'm assuming regular wall paint would work?), and then i need something that can be used for details but will also hold up well.

2) do i need to do anything to the wall before i paint (like primer or something)? i've never painted walls (inside or outside), so i don't know how that kind of thing works.

and 3) is there anything i can use to seal the paint when the mural is done? something that can be used large scale...

i would prefer things that i can easily get locally (from places like a.c. moore, home depot, etc) since i need to start the mural asap. thank you!