Can anyone tell me how to flip a layer horizontally or vertically. I
basically want a helmet to face the other way.

In the Effects Palette, under Image (I think) select "Flop" for Horizontal, "Flip" for Vertical.

I think Kenton Thought this was an editor question and not Deko. 

Or is it the same in Deko Kenton?

Ack!  you're right BLKDOG, that's what I get for only perusing the "Active and Unanswered" Topics.  Come to think of it, I thought the question was worded strangely ...  lol.  I really should pay more attention to what forum the post is being made in. 

I guess I just assume that everyone uses Media Composer on a Mac....  (that superego came free with my MC and MacPro purchase last year)

 One of the reasons I suggested a more prominent banner identifying what Forum you're at when replying in the "New Avid Site" thread.