Decorating Ideas - Idea Exchange
Another active bulletin board on home decorating. I especially like this one.

HomeArts Discussion
Another good bulletin board, hosted by the folks at Hearst.

ROO Crafts Bulletin Board
Although the focus of this site is crafts, you'll also find threads on decorating here.

Usenet - alt.architecture.int-design
Usenet newsgroup for general discussions on architecture and interior design topics