Don’t do what seems to be possible…
You can use the possibility to change the WordPress constants WP_CONTENT_DIR and WP_CONTENT_URL in your wp-config.php.
BUT it really, really, really, really is not recommended.
Why? not recommended??
It’s pretty easy: Just do a cross file search (with your IDE or for e.g. Notepad++) for wp-content and you’ll find it hardcoded it many places. Some of the stuff will still work, but some wont. Yeah, I’ve already tried that.