I recently bought a viglen MPC, and installed Xubuntu it using some very good instructions from Andy SC. I added a USB dongle for wireless, and another one for bluetooth (for later experiments). I then linked my current cost meter to it, to try out some code from Dale Lane's blog. I first needed to install a number of pre-reqs, so I thought I would document them here.

First, I expanded the currentcost-python.zip into a directory, and ran the code:
sudo python currentcost.pyc

This gave an ImportError for module wx. Although I tried installing easy_install, this did not install anything successfully for me, so I followed these instructions to install the wxpython modules. Next, the following commands allowed the other pre-reqs to be installed:
sudo apt-get install python-numpy
sudo apt-get install python-matplotlib
sudo apt-get install python-serial
sudo apt-get install python-simplejson
sudo apt-get install python-pysqlite2

The application then worked! To determine which port to use, I typed:
dmesg | grep tty

The third line of the output said "converter now attached to ttyUSB0"
When you connect, the port should therefore be: /dev/ttyUSB0