The directions at Ubuntu Wiki apt-get source linux-image-$(uname -r)
and askubuntu question Where can I find the source code for the Ubuntu Kernel? don't work…
sudouser@64bitws:~# uname -r
3.2.0-24-generic
and
sudouser@64bitws:~# apt-get source linux-image-3.2.0-24-generic
Reading package lists... Done
Building dependency tree
Reading state information... Done
Picking 'linux' as source package instead of 'linux-image-3.2.0-24-generic'
E: Unable to find a source package for linux
Looks like you can use Ubuntu Software Center…
…but it's very slow ⋯about 1KiB/s