Found a very interesting project in the form of VDXtoSVG, which lets you convert from Visio XML files into the more standard SVG format. I was looking at how this could be used with various projects such as Inkscape and Dia.
It is basically an XSLT which enables a Visio file to be converted to SVG.
One point of interest is that it will not run through Xalan. I have only gotten it to work with Saxon.
