I agree with Mathias.  My very wise art teacher once told me that a traditional art background is imperative for digital art.  And boy was he right!

Nice, looks like you got the pixel side down, but the 3D part is, well, a cube.  I'd like to see what it looks like once you've improved!

I use zymic.com.  It's a little difficult to set up, but once you've got the site up and running it's a breeze.  The only problem I have with it is there are only a few filetypes you can upload.  You can request more, but it takes a while for the requests to be reviewed.

A free host gives you more control and more options.  You can embed a blog into your website that you made with Wordpress or Blogger (formerly Blogspot) and have other pages, too.

I like the sandy tiles, but the mountains seem off.  The moon is behind the mountains, so the light should be most concentrated on the back, not the left side like it is now.