A recent thread on clp offers a few interesting links to presentations (not all the thread has already been stored on google groups at the time of this writing):

• Mike Fletcher's presentation on metaclasses
• David Mertz's & Michele Simionato's Metaclass Programming in Python (part1 | part 2)
• Alex Martelli's presentations

Very interesting stuff but I suspect you know about most it already if you're a Python developer. =)