ThinkPad 11b/g/n Wireless LAN Mini-PCI Express Adapter II
This chip is supported by the rtlwifi/rtl8192se driver, which is planned for kernel inclusion in 2.6.39. There are two other options available, a Linux driver available for download from Realtek, or ndiswrapper. (Ubuntu 10.4 support it now).
The rtlwifi driver which supports this chip will be included in kernel 2.6.39-rc1. Until that is released you can install the driver from the wireless-next kernel tree or, if you are running the latest stable kernel, build only the drivers from the compat-wireless branch.
See http://linuxwireless.org/en/users/Download/ for instructions about installing compat-wireless.
Realtek Linux driver
The Realtek Linux driver for this chip can be downloaded from the Realtek website
More information about using the Realtek native driver in Ubuntu: 
Please note: use of this driver on Lenovo systems results in unpredictable fatal crashes on some systems! It's is *not* advised to choose this driver.
One method that appears to drastically reduce the crashes and connection drops is to comment out "-DENABLE_LPS" from the Makefiles while building the Realtek Linux driver. This also reduces the "noise" in the syslog kernel messages generated by LPS. However, it may reduce the battery life since LPS is an acronym for Low Power State.
* Connections randomly drop out after a few minutes (seems to be fixed in version 015) This problem has been observed with version 015 too. Realtek has been contacted about the problem. * When using WPA Enterprise, entire system will freeze after a few minutes, requiring reboot * Freezes also happen with Ad-Hoc mode from time to time
More information on using the Windows drivers with Ndiswrapper can be found here:.