Courtesy of Alan Lepofsky, but worth repeating here, since it might be the first time I've seen basic material published on developing Domino applications.
Building Databases with Domino Designer 7
Speaking of which, a long time ago I lost a battle to change our terminology from "database" to "application". Do you think users (not seasoned Domino developers, but newer ones are ok) understand they are making a database or an application?
Domino Development Tutorials