Theravada
Links
Abhidhammattha-sangaha
http://www.palikanon.com/english/sangaha/sangaha.htm
Manual of Abhidharma psychology of consciousness and Buddhist metaphysics translated by Narada Thera.
Lectures in Abhidhamma Philosophy
http://web.ukonline.co.uk/buddhism/thitla2e.htm
Popular talks on the basic categories and conception of the Abhidharma philosophy and metaphysics, by Ashin U Thittila.