Carthik.net has a good summary on must reads for moving from Movable Type to WordPress.
LibraryPlanet just wrote up a migration strategy (and provided code) that encompasses how to use WordPress 1.2 new slug feature to support the MT keyword-based shorter file names.
If anyone else has any links related specifically to exporting out of MT and importing into MT, please let me know. Especially if you’ve run into problems and have work arounds.
PapaScott has some MT Export Gotchas to watch our for.