A home floor plan is an excellent visual way to inform your guests of your layout. Go ahead and spend some time having fun with these resources:
FloorPlanner.com – FREE to use. This is the one I used for my floor plan.
CubiCasa – send them your sketch, you get a floor plan.
Floor Plan Marketing – They'll do the work for you
Roomsketcher – they have a free version, 3D will cost you
Sketchup – free and paid versions.
And yes, there is an app for that: