Civ III is relatively easy to do unit graphics for provided you have the right utilities.  I've never tried making units for Civ IV but my understanding is that Civ IV is considerably more complicated with respect to units.  Civ III you just make one set of animations which are seen from the same angle and zoom all the time.  Civ IV you need to be able to zoom in on a unit to see its nose hairs.  I'm not sure if Poser can be used for this but if you go to the Civfanatics forums there are tutorials on how to create units for Civ III and IV.  :)

EDIT: Yes the units are animated.  :)

EDIT 2: If you ever decide to do some of your own Civ III graphics let me know and I can help you get started.  :)

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