I realize that I'd like to have a version string added to my diagrams, is there any good way to do this? I'm thinking I may just use the argument space, because I largely want this for printing them.

Thank you very much for your post, xenocide.

How about these ways to add a version string?

** add a note or text on a diagram
You click [Note] or [Text] on the Tool palette and put on the diagram

** Print Setup(Diagram)
1. go to [File]-[Print Setup(Diagram)]
2. [Page] Tab, you check off the option "Print by using the print setting for the project"
3. [Header and Footer] Tab, edit or add Header/Footer

If you have any questions, please let us know.
We're always happy to hear from you.

Best regards,
Astah Team

only problem with the print option is it seems to require I hook a printer up.. there doesn't appear to be an option like print to pdf which allows me to take the file to another computer to print.

Correct. So the print option isn't applicable to you.
We've received a few requests for printing to PDF and etc. So its on our user-wish list. (I see that you've already sent this feature request before. )

So using the argument space as you said or using "Note" on diagrams would be the way for now.

Thanks,
SJ