Modula-3 - Growing article, with links to many related topics. [Wikipedia] - http://en.wikipedia.org/wiki/Modula-3
Modula-3 Reference and Tutorial - A reference and tutorial on the Modula-3 language and programming system. - http://www1.cs.columbia.edu/graphics/modula3/tutorial/
Persistent Modula-3 - An extension of the Modula-3 programming language that supports orthogonal persistence and transactions. - http://www.cs.purdue.edu/homes/hosking/pm3.html
m3gtk - Modula-3 binding to GTK Toolkit. - http://www.scatcat.demon.co.uk/m3gtk/
Object-Oriented Language: Modula-3 - Offers a listing of mailing lists, resources, archives, links to FAQs, and past conferences. - http://www.cetus-links.org/oo_modula_3.html
Modula-3 Resource Page - Links for implementations, mail lists, FAQs, newsletters, bibliographies, OS specifics. - http://www.m3.org/