Here's a collection of links to sites where you can find craft shows to participate in.

State Arts Sites - Your state likely has an arts commission or similar agency to help out artists, most also have event calenders to help you out.

Indie Craft Shows
- Indie Craft Shows is a directory of indepedently-run craft shows featuring handmade goods.

Festival Network Online - Find music festivals, craft shows, art festivals & fairs in the US and Canada

CraftLister - lists 50,000+ events year