an example snippet for wrestling with python's datetime formatting to create RFC 2822 compatible times

rfc2822.py

from email.utils import formatdate
from datetime import datetime, timedelta, tzinfo

"""
prints the current time and time from three hours ago in RFC 2822 (email) format
stu@sente ~ $ python rfc2822.py
Wed, 21 Dec 2011 16:45:46 -0500
Wed, 21 Dec 2011 13:45:46 -0500
"""

now = datetime.now()
delta = timedelta(hours=-3)

newdate = now + delta

print formatdate(float(now.strftime("%s")),tzinfo())
print formatdate(float(newdate.strftime("%s")),tzinfo())