They appear to be saved as resource fork icons, which makes extracting them a bit of a pain. This method seems to work:
Voila!
Pasting into Photoshop seems to disregard the transparency. I'm sure an Applescript could be set up to do it automagically, but it's not hugely time consuming to do it by hand.
- Get info on the file in the Finder.
- Click on the icon in the upper left corner and copy.
- Open Preview.
- Select "New From Clipboard" from the file menu.
- Save as a PNG.
Voila!
Pasting into Photoshop seems to disregard the transparency. I'm sure an Applescript could be set up to do it automagically, but it's not hugely time consuming to do it by hand.