Here is a list of useful books for clothing, sewing and other accoutrements, should you wish to make your own historic clothing:
Soldiers' Accoutrements for the British Army 1750-1900, by Pierre Turner
Men's Garments 1830-1900: A guide to pattern cutting and tailoring, by R.I. Davis
The Cut of Men's Clothes 1600 - 1900, by Norah Waugh
The Cut of Women's Clothes 1600-1930, by Norah Waugh
Corsets and Crinolines, by Norah Waugh
Patterns of Fashion 1: Cut and construction of women's clothing 1660-1860, by Janet Arnold
Patterns of Fashion 2: Englishwomen's dresses and their construction 1860-1940, by Janet Arnold
Period Costume for Stage and Screen 1800-1909, by Jean Hunnisett
Period Costume for Stage and Screen: Patterns for Outer Garments, Book 1; Cloaks, Capes, Stoles and Wadded Mantles, by Jean Hunnisett
Period Costume for Stage and Screen: Pattern for Outer Garments, Book 2; Dominoes, Dolmans, Coats, Pelisses, Spencers, Calashes, Hoods, and Bonnets, by Jean Hunnisett
Authentic Victorian Fashion Patterns: A Complete Lady's Wardrobe, by Kristina Harris
The Dressmaker series, by Izabela Pitcher (Prior Attire)
The American Duchess Guide to 18th century Dressmaking, by Lauren Stowell and Abby Cox
Stitching La Mode: Patterns and Dressmaking from Fashion Plates of 1785 - 1795, by Carolyn Dowdell
Pattern companies and other useful links for historic clothes:
Lulus.com Sewing patterns and guides (Thank you Katie for the link)
Halloweencostumes.com (Thank you Olivia for the link)