Maintained by the MMA (MIDI Manufacturer's Association), this is THE site to learn about MIDI from the people who dictate the official evolution of the protocol.
Online community for musicians with articles, reviews, forum, and links pertaining to just about every aspect of musical gear.
Creators of the I-CubeX system.
Bome's homepage. Author of MIDI Translator, Mouse Keyboard, and other related software.
MIDI-OX and MIDI Yoke|
Software tools for observing, manipulating, and routing MIDI.