Good artists are harder to find than good Java programmers, for sure. I think because programmers can usually make decent money at their day job, and have the time and inclination to work on games in their spare time. Whereas artists have a hard enough time making ends meet as it is, much less donating their spare time for free…
We have tried a combination of using (paid) interns, and downloadable artwork from art sites, and part-time graphic artists who are working for sweat equity. None of them are 100% satisfactory, not like it would be to have an experienced game artist at your beck-and-call.
You could try advertising on various sites, but if you can’t pay people something (at least food) then it’ll be pretty hard to find them.
I’d recommend trying to find art school students who would work for the job experience, or for as close to free as you can get them. You should definitely review their portfolios and filter on style before picking one, because the only thing harder than finding a good artist is trying to convert one to your “style”…
BTW – your screenshots look very nice! I haven’t tried the demo yet because my machine at work has to be “corporate standard” and doesn’t have the right JVM…