yappcap is a Pythonic wrapper for the libpcap library. It aims to support as much of the libpcap API as is practical to implement in Python with complete documentation and active support.

make && sudo make install

or

sudo python setup.py install

Starting a capture on an interface and saving all packets on port 5060 to a save file:

>>> import yappcap
>>> p = PcapLive("eth0", timeout=1000)
>>> p.activate()
>>> p.filter = "port 5060"
>>> p.loop(-1, None)

Full documentation at http://otherwiseguy.github.com/yappcap/