The Python programming language is used for most parts of Freevo. There are good tutorials on the language website, it does not take a lot of effort to learn the basics. Most of the Freevo developers did not know Python before starting to work on Freevo, but picked it up in a matter of a few days.
Start by reading this page. You can also check out Magnus Lie Hetland's Instant Python which is a good short introduction to Python for programmers.
Please check out the CodingStandard and the Python Style Guide for more info about how to use Python for Freevo.