Articles worth taking a look at:

• Freenet XML-RPC Interface Specification
• Freenet and XML-RPC (Note: The link is to a file that resides within Freenet itself so you must have Freenet installed in order to view it)
• The Evolution of RSS

The first two articles are information on how to write a Freenet client using the new XML-RPC client so your client can be language independent (most existing Freenet clients are Java based because the reference implementation is written in Java and the clients utilize the reference implemenation code). The last article is a nice overview of RSS, all its various versions, strengths, weaknesses, version compatabilities, most anything you might want to know.