This is Tkinter tutorial. It covers the basics of GUI programming in Python with Tkinter. The tutorial is suitable for beginners and intermediate programmers.
Tkinter is a Python binding to the Tk GUI toolkit. Tk is the original GUI library for the Tcl language. Tkinter is implemented as a Python wrapper around a complete Tcl interpreter embedded in the Python interpreter.
There is a full Python tutorial on ZetCode. The original Tk toolkit in Tcl language is covered in Tcl/Tk tutorial. Tutorials for other GUI toolkits for Python language are PyQt4 tutorial, PySide tutorial, wxPython tutorial and PyGTK tutorial.