Yay challenge 31 completed! This one was a lot of fun. I liked the way my code turned out too. I think it looks quite clean, and I used functions that call other functions. Pretty nifty.

Challenge31.py

# Write a function that takes two base-26 numbers in which digits are represented by letters with
# A=0, B=1, Z=25 and returns their product using the same notation. As an example, CSGHJ x CBA = FNEUZJA.
# Your task is to write the base-26 multiplication function.


base26 = {'A':0, 'B':1, 'C':2, 'D':3, 'E':4, 'F':5, 'G':6, 'H':7, 'I':8, 'J':9, 'K':10, 'L':11, 'M':12,
          'N':13, 'O':14, 'P':15, 'Q':16, 'R':17, 'S':18, 'T':19, 'U':20, 'V':21, 'W':22, 'X':23, 'Y':24, 'Z':25}
base26rev = {0:'A', 1:'B', 2:'C', 3:'D', 4:'E', 5:'F', 6:'G', 7:'H', 8:'I', 9:'J', 10:'K', 11:'L', 12:'M',
          13:'N', 14:'O', 15:'P', 16:'Q', 17:'R', 18:'S', 19:'T', 20:'U', 21:'V', 22:'W', 23:'X', 24:'Y', 25:'Z'}


def convert26(string):
    """takes a string and returns the equivalent base 26 integer."""
    string = string[::-1]
    power = 0
    total = 0
    for i in string:
        total += base26[i]*(26**power)
        power += 1
    return total


def multiply(set1, set2):
    """ Takes two strings converts them to base 26 equivalents and multiplies the two together.
    Then returns an integer total.    """
    num1 = convert26(set1)
    num2 = convert26(set2)
    total = num1 * num2
    return total


def revert26(number):
    """converts an integer to base 26 string equivalent and returns that string. """
    revertNum = ""
    while number > 0:
        remain = number % 26
        revertNum = base26rev[remain] + revertNum
        number = (number - remain) / 26
    return revertNum


print "Enter some letters to multiply at base 26:"
first = raw_input("set 1 >> ")
second = raw_input("set 2 >> ")
first = first.upper()
second = second.upper()
print "Thank you...thinking..."
print "Those letters represent numbers in base 26: "
print "set 1: %d and set 2: %d" % (convert26(first), convert26(second))
print "Multiplying these together we get:"
print "%s X %s = %s" % (first, second, revert26(multiply(first, second)))
print "Or, as viewed in base 10:"
print "%d X %d = %d" % (convert26(first), convert26(second), multiply(first, second))