loadMovieClip questions! and movement q

well i suck at action scripting but i know there is a way to load movies clips lets say when a button is pressed. now lets say when the user clicks on another button is there an unloadmovieclip action that tells it when its unloaded may be to go to another frame???
im kind of confused about this (nor do i know the right way to post the action) I searched flashkit.com and kirupa.com with no success

and one more feature i have a question about

lets say i want something to follow the mouse but only in the x access and i want it to be at a specific area in the scene (x200)

well heres the loadMovie stuff:
http://www.kirupa.com/developer/mx/full_site2.htm

http://www.kirupa.com/developer/actionscript/scriptable_masks.htm

thats the thing to your second problem, just without the masks…

isnt he loading the .swf dynamically???

all i want to do is when a user clicks a button the animation pops up from left to right

and when he presses another button the the animation (movieclip)goes from right to left

instead of using goto and play?? get what im trying to do?