True, and that is great, as I believe I've posted in a thread about that, but still, it can be very handy to be able to download it as a pdf file as well. How I ended up finding that is that I was working on my custom dungeon project and then realized I needed to consult the original DM manual to look something up and also realized that sometimes I'm working on my dungeon in places where I don't have any internet access and that having a pdf of the manual would be very helpful for those situations, to I did a search and found someone I could d/l it from.
Actually, it would be a good idea to collect any pdf scans of DM related books, manuals and game guides and put them up on our own servers, that way we could make sure they're available to our members and guests at any time.
EDIT: I'd be willing to search the web for them myself if someone here wants to set them up on our download site.