It's that time of the year.
To find a farmers' market near you, let the government help you: click.
For heirloom tomato transplants, hook up with Catalpa Ridge Farm. They're always at the Ramsey market the Saturday after Mother's day (May 15th, 2010). We had excellent luck with their transplants last year. Once you grow and eat your own heirloom tomatoes, you'll never eat a supermarket tomato again. Come to think of it you shouldn't have been eating them in the first place.