this is a download from url script. It's been customized to fit inside maya and with a UI.

download.py

def download(self):
    gMainProgressBar = mel.eval('$tmp = $gMainProgressBar')
    try:
        hdr = {'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11',
               'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
               'Accept-Charset': 'ISO-8859-1,utf-8;q=0.7,*;q=0.3',
               'Accept-Encoding': 'none',
               'Accept-Language': 'en-US,en;q=0.8',
               'Connection': 'keep-alive'}

        req = urllib2.Request(self.url, headers=hdr) 
        temp = cmds.internalVar(utd = True)
        fileName = temp + self.folder
        chunk_size=5000000
        cmds.progressBar( gMainProgressBar,
                        edit=True,
                        beginProgress=True,
                        isInterruptable=True,
                        status='Downloading Characters ...',
                        maxValue=100 );
        fileWrite = open(fileName, 'wb')
        cmds.progressBar(gMainProgressBar, edit=True, status='Connecting to server....');
        response = urllib2.urlopen(req);
        cmds.progressBar(gMainProgressBar, edit=True, status='Writing data....');
        self.total_size = response.info().getheader('Content-Length').strip()
        self.total_size = int(self.total_size)
        self.bytes_so_far = 0
        while 1:
            chunk = response.read(chunk_size)
            fileWrite.write(chunk)
            self.bytes_so_far += len(chunk)
            if not chunk:
                break
            self.chunk_report()  
        cmds.progressBar(gMainProgressBar, edit=True, endProgress=True)
        fileWrite.close()
        cmds.progressBar(gMainProgressBar, edit=True, status='Unzipping file....')
        zip = zipfile.ZipFile(temp + self.folder)
        zip.extractall(self.dir)
        sys.stdout.write('\nFiles Installed!');
        self.populateProjects()
    except Exception as e:
        sys.stdout.write(str(e));
        sys.stdout.write('\n Failed to download file: ' + self.folder + ' See HELP in the Long Winter menu if you\'re stuck.');
        cmds.progressBar(gMainProgressBar, edit=True, endProgress=True);