How to create iterface SPI with Python?
This is a good starting point: http://hipstercircuits.com/enable-spi-with-device-tree-on-beaglebone-black-copy-paste/. Also read the comments below the blog post, there is a lot of useful information in there.
You can find a newer version of Py-SPI is here: https://github.com/doceme/py-spidev
Some explanation of how Py-SPI works: https://projects.drogon.net/understanding-spi-on-the-raspberry-pi/
Hope this helps,