There was a demo, but it was pretty poor. It was running on the old system that's buggy as hell. It was a decent introduction to the game itself with a nice snippet of the beginning story and a bit of a fun sidequest, but the poorness of the battle system really doesn't help it - the Pokémon don't gain exp, it's laggy, you can't switch... sigh. Oh, and the weather system appears to kill some people's computers.
Once Baskinein's made the basics of the battle system, you'll be due a new demo methinks. As our scripter, he's built the systems from scratch in a much more efficient way and it definitely acts much more like the real thing
In the post with the demo information, I explained that you need to install the fonts from a folder that comes with the demo files, conveniently titled "FONTS". At this stage, I'd recommend waiting a little while for the next, much better demo, unless you're very curious about the game.