The 2.3.99-pre5 kernel is available.
There is also a SuSE installation kit available.
These are available from the project's download page : http://sourceforge.net/project/filelist.php?group_id=429
I've put the project's code in the lxr source browser. This allows you to browse files and directories as well as search for identifiers. It's at http://user-mode-linux.sourceforge.net/cgi-bin/lxr/http/source
The packages, standalone kernel, and patch have all been updated.
It is available at http://sourceforge.net/download.php/user-mode-linux/patch-2.3.36smp.bz2.
To build it, say yes to SMP during make config, and pass in the number of cpus you want on the command line:
./linux ncpus=2