Tkinter Line Graph module?

I'm looking for a module to draw line graphs in Tkinter. I'm sure I could write up my own, but it would be worthwhile to save the time by finding a module for this project. If anyone knows of a simple module out there, or of any guidance in drawing real time line charts, please enlighten me.

I'll be drawing up charts in real time based on numerical input. Number gets sent to the graphing module, it creates a canvas and starts plotting; and as more numbers roll in, the graph needs to scroll along and refresh at each new input. I've just started toying with Tkinter, so I get frustrated with things as simple as text boxes. I fear the canvas.

Also, can Tkinter save it's graphical output to an image file? Will I need to implement the PIL for that?

Thanks all. :-)