All of Crane’s works are available online at U C Berkeley: http://wordseer.berkeley.edu/stephen_crane/view.php
The Little Regiment
Maggie: A Girl of the Streets. (Searchable corrected text at the Crane Society site.)
The Red Badge of Courage
The Third Violet. This innovative site at OpenLibrary reproduces the page images of the edition and allows viewers to “turn the pages” just as they would with a regular book.