I'm using photoshop as well to correct doggy red eyes..
1. make a selection of the eye
2. feather 2-3 pixels
3. copy and paste so the selection pasted to a new layer (I usually work in layers so I can just delete a layer when I get screwed up)
4. desaturate the new layer.. then press (ctrl?) and click the eye part to make the selection from that eye part
5. create a new later.. fill jet black to the new layer with selection from the eye
6. change the blending of the new black layer to overlay and play around with opacity.
I don't have photoshop installed in my laptop, so I may have missed some steps or even put unnecessary steps in above description. It's been a while since I corrected doggy red eyes too, so the description above is just something that comes up on top of my head.. I will post again on monday when I'm at work. Who knows I can find an easier steps too