Recently I purchased for few bucks on eBay a wireless network adapter with name "EDUP 802.11N". This thread explains how to setup this device on Ubuntu.
I inserted USB wireless adapter on Windows XP and it was recognized as "Realtek RTL8188SU Wireless LAN 802.11n USB 2.0 Network Adapter". Windows didn't have any problem to install its driver automatically but for Ubuntu I had to give some additional effort.
After that I went on Realtek official site (www.realtek.com.tw) where I found that this device is supported on linux platform, downloaded and compiled linux driver. This driver (kernel module) is for kernels from 2.6.18 ~ 2.6.33. Unzip this file and in "drivers" subfolder there is driver archive (tar.gz).
After compilation I got driver "8712u.ko" which I had to start as
>tar zxvf rtl8712_8188_8191_8192SU_usb_linux_v188.8.131.52.20100625.tar.gz
After that my Network Manager recognized my wireless USB and I was able to setup wireless connection as usual.
>sudo insmod 8712u.ko
In order this driver to be loaded at startup (boot), I copied it into /lib/firmware directory and setup startup command in /etc/rc.local file:
insmod /lib/firmware/8712u.ko &