Do you mean festivals? Haven't heard of anyone doing a book fair in a long time. I didn't know they still did them. You'll have a better shot by googling. That way you can find out what events are being carried on in your neck of the woods. You can also check out your local libraries and bookstores. Libraries, especially usually have info on what's going on in the literary world, especially locally.
Participation in book fairs is a great way of promoting a book, it is not only helpful to the newbie authors but established authors can also take a great advantage of various popular book fairs. You can always log into sites like http://www.combinedbook.com to have information about various book fairs.