Hai all...
I want to get different colored bars for labels 'Bill', 'Fred', 'Mary', 'Sue'
can any one please tell me ...as soon as possible.....

#!/usr/bin/env python

The new ticker code was designed to explicity support user customized
ticking.  The documentation
http://matplotlib.sourceforge.net/matplotlib.ticker.html details this
process.  That code defines a lot of preset tickers but was primarily
designed to be user extensible.

In this example a user defined function is used to format the ticks in
millions of dollars on the y axis
from matplotlib.ticker import FuncFormatter
from pylab import *

x =     arange(4)
money = [1.5e5, 2.5e6, 5.5e6, 2.0e7]

def millions(x, pos):
    'The two args are the value and tick position'
    return '$%1.1fM' % (x*1e-6)

formatter = FuncFormatter(millions)

ax = subplot(111)
bar(x, money)
xticks( x + 0.5,  ('Bill', 'Fred', 'Mary', 'Sue') )