Should I use PyXML or what\'s in the standard library?
There's also BeautifulSoup, which has an API some might prefer. Here's an example on how you can extract all tweets that have been favorited from Twitter's Public Timeline:
from BeautifulSoup import BeautifulStoneSoup
import urllib
url = urllib.urlopen('http://twitter.com/statuses/public_timeline.xml').read()
favorited = []
soup = BeautifulStoneSoup(url)
statuses = soup.findAll('status')
for status in statuses:
if status.find('favorited').contents != [u'false']:
favorited.append(status)