Craigslist has the format for advertising local craft shows. Organizers of the event can list their show on the local Craigslist page under the Community section in the Events subsection.
Any craft shows that happen to be listed on Craigslist are likely to be listed as events. After pulling up the list of local events, it's easy to narrow the search results with the qualifiers list on the left side of the screen. Selecting criteria such as Art/Film, Fest/Fair or Sale are likely to produce the best results. Those wishing to advertise a craft fair can log into Craigslist to post the event, select Event/Class from the options and fill out the forms provided.