Should MacPorts be installed as root?
By default, MacPorts installs in /opt/local, which usually needs to be created and therefore MacPorts by default needs root to install and upgrade. However, it doesn't have to be this way. MacPorts can be configured to use any directory you want as its root directory, and according to this page if you set your home directory to be its root directory you can use MacPorts without needing to be root.