entry1 = Entry(root)
entry2 = Entry(root)

def callback_entry1_focus(event):
    print 'entry1 focus in'

def callback_entry2_focus(event):
    print 'entry2 focus in'

entry1.bind("<FocusIn>", callback_entry1_focus)
entry2.bind("<FocusIn>", callback_entry2_focus)