Is there a way to tell portage to use python3 by default then?  I have it here so maybe it is already using python3?  Anyway to know?

I just tried eselect python set 2, the grepped ps when running an emerge --sync:
# eselect python list
Available Python interpreters:
  [1]   python2.7
  [2]   python3.2 *
# ps -ef | grep emerge
root      6242  6127  2 22:29 pts/0    00:00:00 /usr/bin/python3.2 /usr/bin/emerge --sync

So, just the usual.