I am running 11.10 on a Dell Inspiron 9400. I ran lshw & it recognizes the BCM4311 802.11b/g WLAN, but I don't see any wireless connections. This is a dual boot machine & the wireless works fine in Windows.
Try to install the proprietary Broadcom-STA-Wireless-Driver. Go to the dash, search for "restricted drivers" and install it.
I would recommend to open a terminal and install the following:
If "An unsupported BCM4311 Low-Power (LP-PHY) device was found." also install
Instructions on how to install firmware for Broadcom chips.