Boody,
Not sure what you are after but judging on your subject, go to View -
Master - Slide master and insert your textbox there and apply the necessary
animation. The box will appear on each slide, but you will not be able to
edit it on your slides. If you want the textbox only to appear on certain
slides and not on others, make a second master (click on the insert new
master on the master toolbar) and apply the new master to the wanted slides
(slide design task pane, click on the arrow next to your master and click
apply to selected slides, your two masters will be in the used in this
presentation section).
If that is not what you want, report back.