Introduction

Links

Tkinter Doc (pdf) (168 pages)
The Grid Geometry Manager (pdf) (10 pages)

tkinter gui layout using frames and grid
Layout Managers / Geometry Manager
ttk - Tk themed widgets
The Tkinter Canvas Widget
Styles and Themes
The Grid Geometry Manager
The LabelFrame widget (Tkinter 8.5)
Basic Widgets

Tcl8.6.7/Tk8.6.7 Documentation > Tk Commands, version 8.6.7 > grid

Practical Programming in Tcl and Tk (June, 2003 Edition)

www.tkdocs.com
Python 3 Tutorial
An Introduction to Tkinter (Work in Progress) (last update 2005)
Tkinter 8.5 reference: a GUI for Python

Intro to programming with Python and Tkinter
Python - GUI Programming (Tkinter)

Diagrams