Tom,
It sounds like clethra alnifolia. Sometimes called sweet pepper bush,
sometimes summersweet or summersweet clethra, and occasionally
bottlebrush. The bees love it and it makes a nice light honey which
crystallizes quickly and smoothly for great creamed honey.
I doubt what you've seen is a viburnum simply because of the time of
year of the bloom, I believe that even the latest varieties of viburnum
bloom in early summer.
The best picture of clethra I could find quickly is at:
http://gardening.com/Encyclopedia/cgi-bin/PlantHitList.asp?FirstHit=Yes&SearchType=Keyword&Keyword=Clethra
I hope for your bees sake, clethra is the right answser!
Kathy