The first thing I noticed was that the eyes are quite nice. I like the "I'm bored/I'm thinking" feel you're going with, too. Overall it's a good start, but you'll definitely want to do some touching up, mostly with the anatomy.
You've made it a little harder on yourself by having the arms tucked in and all pushed together. It means you're going to be dealing with some foreshortening and will need to use some creative lighting to help give it that appearance. On the lower, left arm it looks like the upper arm is longer than the forearm by a considerable amount. Even though pokemon style characters are far from realistic in their proportions, you still want to have somewhat normal ratios so you don't end up with parts that are too long/short/etc. I'd suggest you push that forearm up a bit to shorten the upper arm. Overall it's a pretty tall sprite.
The hands need the most work though. With the hand on the chin it is hard to make out the fingers. It looks like you're going for some kind of cupping shape with shadow in the center and lighter skin all around it. You might want to try simplifying that and just doing the upper half in shadow. On the lower hand I think you've got the shadows backward. The back of the hand is in shadow when it shouldn't be. Really, since that hand looks closed rather than open you might even get away with using very few shadows or even none at all.
I don't want to keep nitpicking so I'll just say one more thing. You might want to move the right eye a little or the line between the light and shadow on the face. Look at some official sprites:
*bulbagarden.net image removed*
More of the face should be highlighted and the nose should be slightly more off center.
So, yeah, a good sprite and you can do a little more work to make it really good.