Tim Bray has announced that Sun Microsystems has hired Charles Nutter and Thomas Enebo, the developers behind JRuby. Tim's announcement has a FAQ that probably answers many of the questions you have. My favorite bit:
Is Sun responding to hype? Yes, if by "hype" you mean a genuine groundswell of interest in the developer community.
Congratulations to Charles, Thomas and Tim. It's exciting to see Sun supporting this project, and it will be interesting to see what they produce.