Our plan is to try and make the rules configurable, along with races/classes. That way you (or someone else) could create the files that would enable 1-3 edition rules in DC.
Sometime after Wizards took over TSR, they posted the rules concerning usage of their material and one of the paragraphs gave permission to use their AD&D rules in free software. Of course, art and other copyrighted materials were still off limits. That gave me some relief with DC being online. I haven't checked back for alterations to this permission lately.
I don't visit the Wizards site much, but I have heard about some sort of Open Source thing they have going with the 3rd Ed rules or maybe with D20 system. I haven't looked into that and I'm not really up to date on their current stance for using AD&D rules in free software.
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CocoaSpud
Dungeon Craft Development Team
http://uaf.sourceforge.net