Several periodicals dedicated to the Python Programming language exist (some active, some are archives).
Active
In chronological order of introduction:
The Python Papers - Established in 2006, with free downloads of printable issues. Please consider contributing an article to this volunteer-run publication!
Python Magazine - First issue came out in October 2007. Available as PDF. Subscription required, but with some issues downloadable at no cost.
The Python: Rag - First issue came out in July 2009. Available as PDF. Free to download.
Archived
PyZine - Published from 2002 to 2005, the archived articles are now available for viewing online without a subscription.
Python Journal - Published around 2002, the archived articles are available online.