I added in_vgm as a parallel directory in CVS. While it's more already-out-there-as-source, having it in CVS is always good. I suppose this also implicitly puts it under the libPNG licence, but then I'm not terribly fussy about that stuff.
Well, I'd been planning to do it forever. Here it is, in the middle of a whole lot of refactoring; if you get the source, it should compile up OK in VC6 or VC7. I'll do a release when it stabilises a bit.