We've had a lot of discussion of brick ovens over the years in
bread-bakers. Many of the sources are still active.
The Bread Ovens of Quebec, ISBN 0-660-00120-9
Includes complete building instructions (but it's expensive)
Build Your Own Earth Oven by Kiko Denzer
We met the author and saw his oven at Summer Loaf festivals in
Portland, OR in the late '90s. Very nice. The book is $17.95 from the
author, cheaper at Amazon (see Suzanne Lander's post in this digest
for the link).
http://www.intabas.com/kikodenzer.html
http://www.handprintpress.com/books/build-your-own-earth-oven/
Ovencrafters.net
Detailed plans available (expensive)
The Bread Builders, ISBN 1890132055 ($22.86 at Amazon)
Brick Oven Cooking
Information links and a yahoo groups mailing list
http://avalonrecords.com/brickoven/
http://groups.yahoo.com/group/brick-oven/
At bread-bakers.com, search digests for the exact phrase "brick oven"
to read the discussions.
Jeff