It is usually suggested to install a package like appypi in a virtualenv. It is still possible here, but it is recommended to use the meta-style installation process.
As appypi is an app installer, you can use it to install itself. This way, your installation is consistent and you keep everything in the dedicated database. Here is a little script to do this in one shot. You need at least pip version 0.8.1 to do that:
virtualenv -q /tmp/appypi-venv &&
source /tmp/appypi-venv/bin/activate &&
pip -q install appypi &&
appypi install appypi &&
deactivate
After that, you can begin to use appypi, as it is callable in your PATH.
To install appypi for your user only, type:
$ pip install appypi --user
To install appypi system-wide, just type:
$ sudo pip install appypi
If no pip available, try easy_install:
$ sudo easy_install appypi