Rotating or Mirroring a single layer in Photoshop?

I realize that this is probably going to be an easy answer I'm too stupid to see it, but I'm used to PSP and I'm kinda set in my ways with it.  In PSP, when I have multiple layers, and then I want to add a texture and mirror it, all I have to do is Image > Mirror.  But there is no option like that in Photoshop CS3.  I can see where it says Image > Rotate Canvas in PS3, but that's rotating the whole thing.  What if I want to rotate or mirror just the one layer with the texture?  *blush*  Thanks in advance.