I am looking for sites which enable users to give feedback or critiques on any sites for free.
Or for site owners to solicit feedback on their sites for site design and usability? Should not be fee based but instead a social type of site. All feedbacks should be public and not private.
The best one for design critiques is definitely ConceptFeedback.com!
It may not be best though for sites already in operation; or for a complete UX evaluation - since users there are posting single screenshots (hence it's for 'concepts').
Take a look at this site... http://creattica.com/ great for inspiration and feedback.
You might actually want to take a look at all the Envato sites, from their marketplace sites to tutorials. You will find lots of inspiration, and forums where you can actively engage with other designers, developers, programmers, etc.
Its a great place to learn, get inspired, and even make some $$$
Best of luck!!!
Check out dribbble.com and sitejabber.com