PlusCostumeChat

Yahoo group dedicated to discussing anything to do with costuming.
http://groups.yahoo.com/group/PlusCostumeChat

Costumes

A Yahoo group for those who like costumes.
http://groups.yahoo.com/group/costumes/

SCA-Garb

Yahoo group discussing costumes for and relating to the Society of Creative Anachronism.
http://groups.yahoo.com/group/SCA-Garb

Sewinghistoric

Yahoo group for people who love to sew period clothing. Sharing of ideas, troubleshooting, and convention and supplies information.
http://groups.yahoo.com/subscribe/sewinghistoric

Giant Tomato and Other Unusual Costumes

Yahoo group discussing atypical mascot costumes; not fur-suit or sports oriented. Sharing includes such items as foam, inflatable, or basket woven costumes.
http://groups.yahoo.com/group/gtuc/