If you share a scanner using the Open Source SANE project, however, you can use Mattias Ellert's TWAIN/SANE interface to make it available to your Mac applications.
I used a Linux machine to share the scanner using SANE, allowing Macs on my network to use the scanner by connecting to the Linux box. Image Capture, Photoshop and Acrobat work fine with it. More information on my setup can be found here. I just happened to have a Linux machine available, but you can do a similar thing in an all-Mac environment.

