Per Dan Pompei's twitter feed:

Mike Martz resigns from Bears over philosophical differences. Story coming soon at chicagotribune.com

Is this some kind of magical wish fulfillment day for Bears fans?

It certainly seems that way, with the ouster of Angelo, and Martz leaving. A new GM could have a much more attractive looking job than it was even just hours ago, especially depending on how much strength George McCaskey actually gives them.

Now, it could be that the "philosophical difference" was that they told him if he was getting a new contract, he was going to fundamentally change the way he calls games, but it could be that he really, really, liked the influence he had over Jerry Angelo (see: Manumaleuna, McCown)

UPDATE: Quarterbacks coach Shane Day is also out. The Bears are indeed making some very significant changes today. Stay tuned...