Update: Little Black Dress

I am so grateful to everyone and their ideas for where to get dresses for formal military occasions that are modest, modern, and not a bridesmaid or prom dress.  I thought I would pass along another one that I found, Shabby Apple.  www.shabbyapple.com  Like a lot of the sites you suggested, they don't have a huge selection, but if you are looking for a little black dress that would work for a variety of semi-formal to formal events, she has some good stuff.  She also has maternity dresses and doesn't charge for shipping if you are exchanging a dress because it is the wrong size!  Some of the other retailers that were also suggested and have some great stuff include, MikaRose, Sydneys Closet, and big department stores if you happen to be in the intermountain west.