ANTIQUES & COLLECTIBLES INFORMATION RESOURCES
Porcelain
An essential read for all serious collectors or anyone with an interest in Chinese and Japanese porcelain.  Gotheborg.com has an extensive list of Chinese and Japanese makers' marks, a brief history on China and Japan, and backgorund information on the various factories, plus a glossary of porcelain terms.  Gotheborg.com is a reference point for many of the fine websites specializing in Chinese and Japanese procelain.
Ceramics & Pottery
Glass
Costume/Fashion
Multi-Topic (including Art Deco,
and Art Nouveau)
Collectics' Reference & Education Program section is an excellent resource for an overview on various topics related to antiques and collectibles.  The entire site is a large, eclectic, mix of consignment shop, antiques & collectibles, mall, bookstore & book reviews, reference information, a monthly Arts & Events magazine, collector quiz, collecting directories, and museum featuring Art Deco, Art Nouveau, and Arts & Crafts design from 1890-1935.
A wonderful overview of reference information for glass collectors with a brief history of glass from the15th century to the early 20th Century.
The Abcir Group of Companies

Antique British Ceramics Internet Resource - information resource for British Ceramics (Belleek, Coalport, Doulton, Minton, Royal Worcester and Wedgwood) with information on factories, the products, designers, modelers, and painters.
The Antique Worcester Porcelain Internet Archives - information resource and meeting place for collectors and dealers of antique Worcester porcelain including examples of more than 450 painters and modelers from 1862-1962, marks,date codes and registration marks.
La Couturiere Parisienne
Wonderfully depicted history of costume design from the 14th centruy to early 20th century. This site is a member of "Costume Ring", a website ring that brings together websites sharing the same interests and mission. The webring is dedicated  to providing costume information.  There is a link to the ring (and member sites) from this site.