Tested on WinXP, Python 2.6 (3.x also tested) after installing pywin32 (pywin32-214.win32-py2.6.exe in my case):
import win32api, win32con
def click(x,y):
win32api.SetCursorPos((x,y))
win32api.mouse_event(win32con.MOUSEEVENTF_LEFTDOWN,x,y,0,0)
win32api.mouse_event(win32con.MOUSEEVENTF_LEFTUP,x,y,0,0)
click(10,10)