I tried the iTunes RSS generator at http://itunes.apple.com/rss/generator/ to download the newest 300 games, which gave me the RSS Feed URL http://itunes.apple.com/us/rss/newapp
yeah, it's fairly broken.
to get more data you can sign up for the enterprise data feed program. it ain't pretty.
http://www.apple.com/itunes/affiliates/resources/documentation/itunes-enterprise-partner-feed.html