I've noticed on my travels (and whilst doing a couple of  Google searches for JoSQL, I find it interesting to see how it "spreads", especially since you can track the version numbers ;) that a couple of folks have picked up JoSQL and written about it, providing useful resources for "usage" of JoSQL. Now, given that the person who wrote the code is rarely the best person to describe it, I thought I'd list these so that others can benefit from them.
Link:  http://www.jroller.com/page/javelotinfo?entry=the_joy_of_josql
Fred has evaluated the use of JoSQL vs  H2 RDBMS for performing aggregations/queries in a project he is developing. In Fred's opinion JoSQL resulted in less code and better performance. The other thing to note is that, as Fred experienced, care needs to be taken in constructing your query to ensure that JoSQL does the least amount of work to get the job done. (As a rule of thumb, if your query feels like it's slow then it could probably benefit from some tuning. Please feel free to  contact me (Gary) for assistance with any troublesome queries.)

I would note though that Fred's use case is suitable for using JoSQL. I would never recommend using JoSQL where a RDBMS is more suited, whilst JoSQL is a useful tool it should never be used in situations where a more suitable tool would be better.

Link:  http://www.informit.com/guides/content.asp?g=java&seqNum=230
I contacted  Steven Haines a while ago about JoSQL since he was looking for "cool tools", and of course being a narcissist(!) I obliged. Steven has written an interesting introduction to JoSQL which is good for those looking for a "starter" guide.

Link:  http://technology.amis.nl/blog/index.php?p=806
Again provides a quick overview of JoSQL and it's usage. They've even helpfully put together a quick JDeveloper/Eclipse project so you can try it out. One important point to note: they indicate (and my own tests back this up) that searching through 1,000,000 objects takes about 1.5s.

In my (humble ;) opinion, if you have 1,000,000 objects to search through then you shouldn't be using JoSQL, get yourself a good RDBMS like  MySQL,  PostgreSQL or  Oracle or use an OODBMS like  db4o. JoSQL can solve a number of problems but it shouldn't be used for mass data management, the use of reflection and lack of indexes make it completely unsuitable.

Link:  http://www.devx.com/dbzone/Article/30291
 Laurence Moroney has written a very useful article about JoSQL. He provides a real world example of how to use JoSQL with a Chat Server and Chat Clients. It also serves as a useful "get up and go" starter article.

Link:  http://www.javafree.org/content/view.jf?idContent=57
This article contains information about pairing  Prevlayer with JoSQL. I'm afraid I can't vouch for the usefulness of the article (it "looks" good) because my non-English skills are appalling and Google wasn't able to translate the page either. It does provide code examples though that are understandable.

Link:  http://blogs.bytecode.com.au/glen/2006/02/27/1140984917921.html
Glen is using JoSQL to filter an event queue. One of the issues he faced was how to distinguish between events of varying types in a single List. His blog post has the answer.