I just register to scala-user milling list and read a little tutorial on it. Will Scala be a language used more and more in commercial applications? I mean I can write it to my resume and look for a good job.
My hunch is it will get used more and more but, as of now, if you search for scala & java on monster.com you won't find any results.
groovy & java returns a number of results. This doesn't mean that learning Groovy will land you a "good job", it just shows that Groovy has some ground in the market.
If anything, I'd encourage everyone to learn at least one other language on the Java platform. For me, it has really enriched my programming knowledge and learning different programming paradigms has even made me a better Java programmer.