Dungeon magazine (118-121) came with an enormous and really beautiful 4-part Greyhawk map that illustrated the locations of a great many TSR/WotC dungeons. Issue 118 is very had to find now in hard copy but the map sections can be bought from Paizo. If you need digital, the PDFs of the magazines that Paizo have for sale include high resolution versions of the map sections.
They have a free desktop wallpaper jpeg of the map on their site but it's too low res to use for any but its intended purpose.