Save the image in Poser as a .png file.

Then go to Photoshop and click "File" and open the .png file you saved.  It will show up in Photoshop as an image with a transparent alpha layer.  You can save it back out as a .psd file if you want or you can work on it in .png format and then save it as a .psd file when you're done so that it saves the layers etc.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi