On Tuesday April 10th, he XRuby team announced the release of XRuby 0.1.4, which can can be downloaded from code.google.com. This release feaures a new runtime (written by Dreamhead) that fixes a number of compatibility issues with MRI. According to their website, this release is also "much faster" than MRI, it will be interesting to see what happens the next time Antonio runs his benchmarks.
Upcoming work looks very promising too, Beanworms is working on the debugger, Yuesefa has a Google Summer of Code project to rewrite the XRuby parser to ANTLR 3.0, and Femto has also joined the team and will be involved in the parser rewrite.
The ANTLR 3.0 parser has a lot of potential outside the XRuby project. Since ANTLR 3.0 includes Ruby as a target output language, this may provide a solid Ruby in Ruby parser for other developers to use as well.