The Wilfred Owen Association
http://www.wilfredowen.org.uk/home/
An excellent and exhaustive site. Links to critiques of the major poems.
Wilfred Owen
http://www.poets.org/poet.php/prmPID/305
The poets.org page for the author; a short biography and links to poems.
Wilfred Owen
http://www.warpoetry.co.uk/Owena.html
An amateur but well-done site containing short biographies, essays, and photographs.
The Wilfred Owen Collection
http://www.oucs.ox.ac.uk/ww1lit/collections/owen
Managed by Oxford University's digital archive.
Wilfred Owen
http://www.poetryfoundation.org/bio/wilfred-owen
The Poetry Foundation's page for the poet. A long biography.