There is currently no good support for YAML in Java. YAML is a very nice data format for all people tired of XML (and who isn't?). It's easy on the eyes, easy to understand and easy to write. It's also rapidly becoming the exchange format of choice for many dynamic languages like Ruby, Python and Perl. If you're more interested in YAML, some information can be found at http://www.yaml.org.
Of course there should be a Java implementation for YAML. There exists some old half hearted tries, but nothing that actually works all right. And since JRuby do not have YAML support yet, a Java implementation would help that situation too.
So I've started a new open source project - soon to be hosted at Sourceforge - called JAML. It's very straight forward right now, based on PyYAML right now, since Syck is write-only code, and most other systems were based on automatic lexers and parsers. As soon as the project is public at Sourceforge, I will post a note here. In the meantime, if you're interested in helping out, or looking at the code, send me a mail at ola AT ologix.com.