Maybe this will get you going:

import pylab as p
import datetime as d
from matplotlib.dates import DateFormatter
t = [ d.datetime (2007,9,1,12), d.datetime(2007,9,2,12), d.datetime(2007,9,3,12) ]
t = p.date2num(t)
p.plot_date( t, [10,20,30] )
p.xticks(t)
y = DateFormatter('%Y-%m-%d')
p.gca().xaxis.set_major_formatter(y)
p.draw()

Mark

From: "C M" <cmpython@gmail.com>
Subject: [Matplotlib-users] basic understanding of plotting dates

x = (2007-09-01 12:00:02, 2007-09-02 12:00:02, 2007-09-03 12:00:02)
y = (10, 20, 30)