DOOM wiki
Here is DOOM’s own wiki, a wiki site completely dedicated to everything DOOM.
So if you need any thing DOOM here is the place to find it. Now some of the same source problems that effect wikipedia are the same here, however, generally only DOOM fans go and edit these pages, but that dosen’t mean their info is solid.
and of corse here is Romero’s DOOM wiki page, same basic stuff as the regualr wikipedia page though diffrent picture. But it does have all the levels Romero desgined for DOOM and DOOM II.