I recently ran into the issue of trying to use the aggregator module to read a feed from a page from a server using gzip compression. From my debugging I realized that the drupal_http_request function does not reinflate gzip content and caused errors when I tried to read the RSS feed. I attached a small patch that checks for gzipped data and will reinflate it into a format usable by Drupal.
Drupal running on:
Reading RSS Feed from:
ColdFusion script that generated RSS feed
content type returned: [Content-Encoding] => gzip