Back in May I started looking at what Open Source P2P APIs were available. P2PS looked promising (and even still under active development) since JXTA is probably overkill for this project, but there simply wasn't a critical mass of developers/developmentr compared to what was available for JXTA. As a result there weren't enough sample apps to look or solid programmer documentation. Free Pastry was also a possibility and had more sample apps, but didn't have a rich set of security functionality. Of course if the toolset is designed correctly, it should be easy to swap in different P2P APIs (for example, if the JXTA Ruby bindings become mature enough if we want to deploy embedded nodes that don't require Java)
I was pleasantly surprised when I visited JXSE Java.net Page today (JXSE is simply the Java SE/EE implementation, as opposed to CLDC/J2ME) I was pleased to see that a new version of the programmers guide was only released a couple of weeks ago. This is good news. JXSE is currently at verison 2.5_rc3 so given the early state we are at it makes sense to go with this.