If your main and fill lights are properly setup it doesn't matter
what skin color the people have.

A well exposed image should not have any problems with the relatively minor
differences in skin tone density between black and white skin.   A well
exposed and lighted image should be able to show detail in a black tux and a
white wedding dress.

Black skin reveals bad lighting more than white skin does.  That's why many
black people say they have problems when having their portrait done in the
typical studio where they put a couple brollies on either side of them,
specular lighting gives you specular highlights and you just notice the
problem more when they stand out more on dark skin.

Oh, and that tiny little flash built into your camera is the worst kind of
light.

Look at any department store catalog, look at the leather coats, shoes and
purses.  Does the black shoe look like it got a radically different exposure
than the white shoes?  Does the pretty white model look like she got a
different exposure while wearing the black jacket than the image of any
other item, not a bit.

How do they light black leather goods?  the same as they do other shiny
items like electronic goods, coffee pots and other kitchen utensils.  They
use a large soft light source.   healthy and young skin is nice and shiny
like that too.   All these items are lighted with a large source, twice as
big as the subject usually, and this spreads the highlights out so much that
you can see some detail in them, as opposed to blocked up specular
highlights.   When you have texture in the highlights is when you have a
proper exposure for them.   Get your light source large enough to do so will
spread the light out so enough light will get to the shadow side too.

I suppose you won't be bringing large scrims and light banks to the wedding
dinner, but hopefully you have a flash that allows you to aim it somewhere
besides straight at the subject.   I try to bounce my flash off side walls
as much as possible, and that gives a nice soft light much like a huge
softbox as it bounces off a large area of the wall.

this reply has been echoed to the z-prophoto mailing list at yahoogroups.com

No overall compensation is necessary.  The main problem arises if you
have very dark skin and very pale skin side-by-side.  However, this
problem exists in all weddings already to some extent, since there is
often a contrast between black attire and white attire (bride and groom,
for example).

Use low-contrast film with lots of latitude.  If you have the time and
material, try lighting dark skin with diffuse light, and light skin with
more of a point source(s), and light the dark skin a tiny bit more to
reduce contrast.  That requires setting things up pretty carefully,
though, so it isn't likely to be practical outside a studio.

Shadowless light sources are usually the best choice for very dark
complexions.  You may need to create a compromise that favors this
form of lighting.

Are you ready for a ton of spam to your email account? From the
instructions you gave above for replying, I take it you are trying to
avoid email harvesters. But you forgot to change your email address in
your newsreader. It placed your true email address in the From field and
now is available to the worthless spammers.