Links
I have tried to only list places that sell period-correct merchandise and sites that provide informative, documented research.
The links I can personally Recommend are in Red. If you know of a link that should be added to the list, please let me know.
Fabric, Trim, Sewing Supplies
Merchants, Sutleries
Mrs. Parker's Millinery and Mercantile
Ragged Soldier Sutlery and Vintage Volumes
Farthingales Corsets & Supplies
Original Clothing