Vintagedance.info will be a reference site for vintage dancers, providing links to vintage dance groups, searchable event calendars, temporary home pages for startup groups, and much more.

As a starting point, take a look at the following links:

The P.E.E.R.S. site. PEERS holds about 10 balls per year, as well as weekly dance classes, in the San Francisco Bay Area. The periods range from ancient Greece to the 25th century of Babylon five

Ye Gaskell Occasional Dance Society Holds six victorian balls a year, in Oakland CA

Library of Congress Dance Manual Collection. This collection of dance manual, pamphlets, &etc. was copied from the Library of Congress's American Memory Project and has had a new user interface put around it.

The Lively Arts History Association site is home to many vintage dance groups in Southern California, including The Social Daunce Irregulars, and the Santa Barbra Vintage Dancers

The Dickens Chrismas Fair. If you want to do victorian dancing 'till you drop, come to the Dicken's Christmas Fair, and enter Fezziwig's Warehouse, where it is Christmas Eve. for 9 hours every Saturday and Sunday from Thanksgiving to Chrismas. Join Mr. Fezziwig, his family, employees, friends and neighbors, as they celebrate the true spirit of Christmas with dance and games.

The Dancing Master,1651-1728: An Illustrated Compendium By Robert M. Keller. an on-line compilation of all the dances in all the various versions of the Dancing Master, started by John Playford.

DHDS The Dolmetsch Historical Dance Society, a group in England dedicated to historical dance through the 19th century.

Friday Night Waltz group, has lessons and dancing on (usually) the first friday of the month in Palo Alto. The Victorian Dance Ensemble, based in Pennsylvania, specializing in civil war era dances.
DanceTime Publications, instructional videos &etc.