Critique Project Forums/Websites

Hey guys, I was wondering if anyone knows some good websites or forums that are especially meant to display work for critique. I have taken most of my courses here and another one over on Tuts+ Premium and created my first website portfolio. I am struggling with a few things and would like to know where to go from there. Any suggestions would greatly be appreciated. I do have some questions here for anyone that is willing to offer some input:

What language or possible course here at Treehouse will I benefit the most from learning how to build good solid contact forms. I want to add a contact page to my portfolio and need to know the ins and outs of how data input actually works so that I can deploy it.

Also, I am having a really hard time with my nav list. My goal is to center my ul and the li inside of my navigation id but cannot seem to get it to center at all. I have tried applying marging to all sides both positive and negative and they are not moving at all. I may be targeting the wrong elements. The text align is set to center but as far as moving my links to center in terms of top and bottom, it is simply not working. This is my code: How would you target this? Thanks guys!

<div id="nav">
            <ul>
                <li><a href="index.html" class="selected">Home</a></li>
                <li><a href="#">About</a></li>
                <li><a href="#">Work</a></li>
                <li><a href="#">Contact</a></li>
            </ul>

</div><!--End Nav-->