How to write a program to solve project Euler problem 4

'''
This file is worked on from http://www.s-anand.net/euler.html , Solution of Problem 4 

A palindromic number reads the same both ways. The largest palindrome made from the product 
of two 2-digit numbers is 9009 = 91 x 99.

Find the largest palindrome made from the product of two 3-digit numbers.

'''

n = 0

for a in xrange(999,100,-1):
    for b in xrange(a,100,-1):
        x = a * b
        if ( x > n ):
            s = str( a * b )
            if s == s[::-1]:
                n = a * b
print n