I've downloaded a free Wordpress theme from wordpress.org and this theme has a link in the footer that goes to the website of the developer of this theme (the footer file is not encrypted). I wonder if I can remove this link? The theme is distributed under the GNU General Public License (GPLv2).
GPL allows doing whatever you want with the code (you just have to distribute it under the same license). So removing a link is legal but I think that it is very unethical. Donate the author at least few bucks if you want to do this.
That is really a good move i must say. On the other side if you are using something free (free theme) then you need to keep author links intact as it is. DON.