I just retired a PC and replaced it with an iMac. I was running Express 8.0 (single user version) which doesn't load up on the new machine. Is there an iMac version of Arts & Letters Express?
According to the official website, you don't have the possibility to use this software on Mac OS X because the software hasn't been released for this particular version. However, one possibility is to use Parallels Desktop or Bootcamp. Personally, I advise using Parallel Desktop because you will run Mac and Windows (in a window) in the same time rather than dual-booting through Bootcamp. No, you can't run the app in Mac OS X natively.
Download software (might require purchasing): http://www.arts-letters.com/
Parallels Desktop: http://macdownload.informer.com/parallels-desktop/