Anyway the good folks over at Ubuntu Launchpad have already released a kernel to correct this.
Here is what to do.
Download this file to your home folder http://people.canonical.com/~sforshee/lp710738/linux-image-2.6.38-8-generic_2.6.38-8.42~lp710738v201104200928_i386.deb
now open a terminal and type:
sudo dpkg -i linux-image-2.6.38-8-generic_2.6.38-8.42~lp710738v201104200928_i386.deb
once finished restart PC and wireless should be working.
Update manager will offering you a kernel update as it sees this as a backward step. Make sure when you do future updates you de-select any Kernel upgrades or you will have to do this all over again