probably the best realtime charting for python would be chacos http://code.enthought.com/chaco/ more static charting would be this http://matplotlib.sourceforge.net/
In addition to the ones mentioned by Rosy2, another library that can be used with python, especially to view financial data is Chartdirector. It's a commercial product (about 100$) but if you do not mind a small label with the Company's name you can use it for free. -- KG