One method that works well, and which I generally practice, is to shift the
first honey-super back a fraction of an inch, to leave a ~1/4" opening
across the front of the hive.  An opening is thereby provided at the upper
edge of the brood-chamber.  This was recommended to me by an old-timer who
swore it would do much to prevent swarming.  I'm not sure, but it couldn't
hurt.
 
This opening helps to get the hot stale air out of the brood chamber, aids
in evaporating down the nectar, and the bees will use this space as an
upper entrance as well.  I should add, this is only done on strong colonies.
 
I have never bothered to shelter the gap from the weather, but the bees
haven't appeared to suffer any.  No landing board required, and leave the
regular bottom entrance wide open.
 
On warm evenings during a nectar flow, the bees will line right up along
this upper entrance, fanning away.
 
 >I would like to experiment with the 'upper entrance' notion with my hives.
>Has anyone out there used this type of setup?  I would be interested in
>hearing about the pros and cons of this.  some questions I have are:
>
>1. What do they use for a landing board?
>2. What is the best way to create the upper entrance?
>3. Are you suppose to close the bottom entrance if using the upper entrance?