This guide from the University of Nebraska-Lincoln is a comprehensive guide to undergraduate research journals sorted by field. It includes information about and links to each journal.
"Young Scholars in Writing: Undergraduate Research in Writing and Rhetoric publishes research and theoretical articles from undergraduates on writing, writers, rhetoric, discourse, language, and related topics."
The Naylor Workshop allows undergraduates to become better writing studies researchers. It offers a three days of discussion, consultation, presentations, and networking.