If you want to get an RSS feed from the iTunes app store, you can go to http://itunes.apple.com/rss/generator/. Using the controla on the page, you can get up to 300 of the top free and paid application in any app category. But you can't get a feed that shows you recently released applications. They then give you a URL for your RSS feed based on your selections. I've tried hacking the URL to make it give me recent apps instead of the top apps, but no luck. If anyone figures out how to do this, please add it to the comments.