This week's book giveaway is in the General Computing forum. We're giving away four copies of Arduino in Action and have Martin Evans, Joshua Noble, and Jordan Hochenbaum on-line! See this thread for details.
Since feeds are just web resources, it is possible to use HTTP authentication methods to protect them (basic, digest, etc.). The problem is, very few feed readers can handle password protected feeds -- that's one of the reasons I did cover password protected feeds in the book.