Here is an example working on py2.6 and py3.2:

from scipy.stats import norm
import matplotlib.mlab as mlab
import matplotlib.pyplot as plt
# read data from a text file. One number per line
arch = "test/Log(2)_ACRatio.txt"
datos = []
for item in open(arch,'r'):
item = item.strip()
if item != '':
try:
datos.append(float(item))
except ValueError:
pass
# best fit of data
(mu, sigma) = norm.fit(datos)
# the histogram of the data
n, bins, patches = plt.hist(datos, 60, normed=1, facecolor='green', alpha=0.75)
# add a 'best fit' line
y = mlab.normpdf( bins, mu, sigma)
l = plt.plot(bins, y, 'r--', linewidth=2)
#plot
plt.xlabel('Smarts')
plt.ylabel('Probability')
plt.title(r'$\mathrm{Histogram\ of\ IQ:}\ \mu=%.3f,\ \sigma=%.3f$' %(mu, sigma))
plt.grid(True)
plt.show()

Cheers!