The second one is really cool, but I was wondering what you're doing with the text.

In the first wall paper I think it might help if you anit-alias the text. If anti-alias is on, you might what to soften the edges of the text with a blured stroke, shadow, or glow.

On the second one it seems like there's some kind of garbage pattern rendering around the text. That could be the font you're using, or more likely the quality of the file you're saving it as. When saving as a Jpeg, typically I use save for web (when posting) or I make sure to not go under 8 on the quality.

Hope this helps you in the future.