Just change the direction setting in the Custom Animation task pane. Choose
"from left" in the drop-down.

This depends on what you are animating and what version of PowerPoint you
are using. I suspect you have just added the fly in animation (by selecting
Add Effect > Entrance > Fly In) and found that they are not flying in from
the left but rather from the bottom (this never seemed to me to be the
right default behavior for fly in, but I don't work for Microsoft, and they
often make odd choices for default behavior of things).

In the Custom Animation task pane on the right of the screen (should still
be there right after you added the animation), you should see a list of
animated shapes. Click on the one you want. If you added the fly in
animation, then you should see three pull-down menus. One of them is for
direction. Simply choose From Right from that menu.

--David

This is for 2003 - Select the item, and on the Custom Animantion task pane,
click on Add Effect|Entrance, then Fly in (you may need to go to more if it
is not on the list). Then you will see Direction: From Bottom (the default).
Click on the downward arrow and select from right. Hope this works for you.

J. Old,
Not quite sure what you are after. Select the object you want to animate,
apply an entrance effect in the custom animation task pane (Add effect -
entrance - fly in) - choose on click, from the right, and an appropriate
speed.
If i did not understand you correctly, post back.