Seems like someone pulled another breakage, almost an year after the past one. Please do not upgrade to this version of Python, and if you have problems like the following:
>>> Emerging (1 of 1) dev-lang/python-2.6.5-r3
Traceback (most recent call last):
  File "/usr/bin/emerge", line 42, in 
    retval = emerge_main()
  File "/usr/lib64/portage/pym/_emerge/main.py", line 1555, in emerge_main
    myopts, myaction, myfiles, spinner)
  File "/usr/lib64/portage/pym/_emerge/actions.py", line 434, in action_build
    retval = mergetask.merge()
  File "/usr/lib64/portage/pym/_emerge/Scheduler.py", line 914, in merge
    rval = self._merge()
  File "/usr/lib64/portage/pym/_emerge/Scheduler.py", line 1222, in _merge
    self._main_loop()
  File "/usr/lib64/portage/pym/_emerge/Scheduler.py", line 1369, in _main_loop
    self._poll_loop()
  File "/usr/lib64/portage/pym/_emerge/PollScheduler.py", line 134, in
_poll_loop
    handler(f, event)
  File "/usr/lib64/portage/pym/_emerge/SpawnProcess.py", line 151, in
_output_handler
    buf.fromfile(files.process, self._bufsize)
IOError: [Errno 11] Resource temporarily unavailable
Then please see bug #330937 — at this point in time I have no idea how to solve if you updated already, it’s 3:50am and I’m actually here just because I made a mistake rebooting Yamato and found this out.
Update: we have a quick hotfix for you to apply if you reach this point:
wget http://dev.gentoo.org/~ferringb/fix-python-2.6.5_p20100801.patch -O - | patch /usr/lib/portage/pym/_emerge/SpawnProcess.py
it’s a one-liner, just execute it, then you can simply re-merge Python 2.6.5-r3 and Portage to have the pristine system.