First, an apology. Bad news: Having spent several days, trying different, unsuccessful fixes, losing track of what I tried and in what sequence, I cannot categorically say what is the minimum you must do to get the WiFi working. Good news: with the 2.6.30 kernel and compiling the driver, it does work.

Kit: Samsung N140 (Belongs to my partner. My Samsung N10 Wifi just works). Wireless chip: Realtek RTL8192. Dist: Eeebuntu Standard 3. Kernel: 2.6.28

What has not worked
Installing ndiswrapper and using the driver from the Realtek website; compiling ndiswrapper and using the driver from the Realtek website; merely using the 2.6.30 kernel.

Suggestion
What I suggest is that you compile the driver with the standard 2.6.28 kernel. If WiFi does not work, install the 2.6.30 kernel. If WiFi still does not work, recompile the driver. Perhaps someone with more knowledge can suggest a better solution.

Compile the Driver
Go to the Ubuntu Forums and do as helliewn (3rd post) suggests: download and compile. I did not find I needed to edit /etc/modules http://ubuntuforums.org/showthread.php?t=1348253&highlight=Samsung+N140+Wireless+problems. {As I had already set my Network Connections and was using the 2.6.30 kernel, my WiFi immediately started working}

N.B. I had already compiled ndiswrapper, so I had all the compile stuff. If you need it, follow paragraph 5.1 from here https://help.ubuntu.com/community/WifiDocs/Driver/Ndiswrapper#Compiling%20the%20latest%20version%20of%20ndiswrapper

Install 2.6.30 Kernel
http://www.ramoonus.nl/2009/06/10/linux-kernel-2-6-30-installation-guide-for-ubuntu-and-debian-linux/
Remember to amend /boot/grub/menu.lst to select the new kernel.

Set your Network Connections.