Berkeley: Chaucer's Troilus and Criseyde: Available as complete text or each book separately.
Troilus And Criseyde: Rendered into modern English spelling; this site also includes the text of Robert Henryson's "The Testament of Cresseid" and the translator's prefatory comments. All are in Portable Document Format.
Troilus and Criseyde: Plain Text in original Middle English on a single page.
Troilus and Criseyde: In plain text, or as a zip file, at Project Gutenberg.