Free269 on "Remove "/category/" from the URL and fix sub categories"

Hi guys :)

I want to remove the "/category/" from the URL.
So instead of having: http://www.mysite.com/category/desenhos/
I will have http://www.mysite.com/desenhos/

and the next thing I will want to do is:
If I have a sub item under a category so instead of having:
http://www.mysite.com/category/subcategory
I will have
http://www.mysite.com/Unartistic/subcategory

This is how my menu looks like:
http://i57.tinypic.com/33bhkd1.jpg

I don't know how even to start changing this kinda stuff
never worked with URLs especially not with wordpress.

Thank you :)