I did a quick google search - here are the results
There are several threads which look promising - I suggest you have a look to see which suits you.
thank you so much for your answers
if you dont mind I would like to ask another question related to my first question..
before I asked my question ,I had googled some key words and even though I had found many pages ,most of them were out-of-date and complicated ..I just found a page explains it more simply..http://ubuntuforums.org/showthread.php?t=797804
but it says i have to install some deb files and network manager program.But Network manager program link doesnt work. do you think I have to install network manager ?I think I saw this program already installed on Ubuntu ?
and I would like to ask how to install .deb files..
( as far I learned I will try to copy them in a folder in my flashdisk and then I will run terminal in ubuntu and then I will write this code for every file .)
dpkg -i random_name.deb