#buttonbind.py
from Tkinter import *

# Hold onto a global reference for the root window
root = None


def mouseEntered(event):
    button = event.widget
    button.config(text = "Please Please click me")

def mouseExited(event):   
    button = event.widget
    button.config(text = "Logon")
    
def main():
    global root
    
    root = Tk()  # Create the root (base) window where all widgets go
    b = Button(root, text="Logon")
    b.bind("<Enter>",mouseEntered)
    b.bind("<Leave>",mouseExited)
    b.pack()

    root.mainloop() # Start the event loop

main()