Copying from here: http://www.voidspace.org.uk/python/articles/urllib2.shtml#httperror
The exception that is thrown contains the full body of the error page:
#!/usr/bin/python2
import urllib2
try:
resp = urllib2.urlopen('http://ws.audioscrobbler.com/2.0/?method=user.getinfo&user=notonfile99&api_key=8e9de6bd545880f19d2d2032c28992b4')
except urllib2.HTTPError, e:
print e.code
print e.read()