I am on MacOSx 10.6.8 and I have python 2.7 installed
python -v produces:
Python 2.7.2 (v2.7.2:8527427914a2, Jun 11 2011, 15:22:34)
[GCC 4.2.1 (Appl
My guess is that both pip and virtualenv are from the 2.6 distro. You can check which one the system users with which pip. If you do have other pip/virtualenv install (use which -a pip to find all of them) it might be that you need to tweak your PATH environment variable.
Another thing to note is the installed Python scripts usually have full path to the Python executable. You can see which python pip is using by running head $(which pip)