Display a label while pressing the button in my GUI

[hmmeeranrizvi18 at gmail.com]

Hello Guys,
Here i am creating a GUI which will act as a search engine that will find the results from the browser and save the results as a xls file.
When i typed something in my search box and click the (GO)button.It should display search in progress.when the file is saved it should display done.
How to do that?
My button gets hung for a seconds.We should give any timeout for that?

Here is my script
<python>
from Tkinter import *
import mechanize
def clear_search(event):
    search.delete(0,END)
obj = Tk()
Label = Label(obj,text="Top Findings:",font="-weight bold")
search = Entry(obj,width=100)
search.insert(0, "Enter the value to search")
search.bind("<Button-1>", clear_search)
def fun():
    new = search.get()
    url = "http://duckduckgo.com/html"
    br = mechanize.Browser()
    br.set_handle_robots(False)
    br.open(url)
    br.select_form(name="x")
    br["q"] = str(new)
    res = br.submit()
    content = res.read()
    with open("result1.xls", "w") as f:
        f.write(content)
fun()
Go = Button(obj,text="GO",width=5,command=fun)
Label.pack()
search.pack()
Go.pack()
mainloop()
</python>