Useful things to know

exclusion_list.xml - specifies which class files you want excluded

mc._lockroot is useful for locking your movieclip's root timeline so it remains the same even after being loaded into another mc.

MovieClipLoader in FlashMX 2004
http://whatdoiknow.org/archives/001238.shtml

Darron has written a lot of good stuff
http://www.darronschall.com