One resource that I found incredibly helpful in deciding on my dress silhouette was a book called Vintage Weddings by Daniela Turudich. Unfortunately, the book is out of print, but I was able to get a copy to use through my local library. I still have a few scans from the book and I thought I would post them for you to give you an idea of the book contents.
The neatest thing about the book is that it covers 1910 through 1950, giving various details on each era and it's accompanying accessories. This is extremely helpful to someone that knows they want to have a vintage wedding but doesn't know which style they like the best. By breaking each decade down, Turudich helps to outline the traits that a bride may find suits her personality the best. Below are the dress details from the 40s and 50s, so you can see the difference. You can click on the images to enlarge them.