According to Cyrille Chepelov <chepelov@calixo.net>:
>
> (dia's native file format is gzipped XML; it's quite easy to parse. However,
> I'm afraid XML is not the silver bullet described in the trade press, and
> dia's file being XML won't help loading them into Visio much, unless you're
> ready to write a dia-to-Visio filter in a scripting language able to drive
> Visio, if such a thing exists).
If you have Visio and know OLE programming, you can do that on Windows.
There is currently a company that does this for their own diagramming
software and provide a web service to translate Visio files to their.
If that gives ideas...
Hub