Solution to TicTacToe.py program:

# program TicTacToe.py
# Author: Brenda Student
# Section: CSCI 110
# Date:   March 20, 2011
# Purpose: Use a turtle to play tic tac toe.

from turtle import Pen as Turtle

yertle = Turtle( )

def drawBoard( ):
    yertle.up( )
    yertle.goto(-75, -25)
    yertle.down( )
    yertle.forward(150)
    yertle.up( )
    yertle.goto(-75, 25)
    yertle.down( )
    yertle.forward(150)
    yertle.up( )
    yertle.goto(-25, 75)
    yertle.right(90)
    yertle.down( )
    yertle.forward(150)
    yertle.up( )
    yertle.goto(25, 75)
    yertle.down( )
    yertle.forward(150)
    yertle.left(90)

def drawX(row, col):
    yertle.up( )
    yertle.goto(-70+col*50, -30+row*50)
    yertle.down( )
    yertle.right(45)
    yertle.forward(57)
    yertle.up( )
    yertle.left(45)
    yertle.backward(40)
    yertle.left(45)
    yertle.down( )
    yertle.forward(57)
    yertle.right(45)


def drawO(row, col):
    yertle.up( )
    yertle.goto(-50 + col*50, -70 + row*50)
    yertle.down( )
    yertle.circle(20)

drawBoard( )
player = 1
answer = raw_input("Would you like to play tic tac toe? ")

while answer == "yes":
    moveRow = input("What row (0 - 2) is your move in? ")
    moveCol = input("What column (0 - 2) is your move in? ")
    if player == 1:
        drawX(moveRow, moveCol)
        player = 2
    else:
        drawO(moveRow, moveCol)
        player = 1
    answer = raw_input("Would you like to continue playing? ")

print "Game over!"