Editing

DXEditing.com
A website with tutorials on how to make modifications for Deus Ex.
http://www.dxediting.com/

Tack's Deus Ex Lab
Steve Tack's Deus Ex SDK tutorials organized in a book-like format.
http://www.planetdeusex.com/tack/

Universal Constructor
Level design tutorials.
http://www.rpgplanet.com/deusex/constructor/