Website theme help

I am some what of a noob at doing html and CSS files. Here are some of the major problems I have so far:

http://pixelsmashers.com/forum/blog.php/

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1- I can’t seem to fully center the news posts.

2- I can’t seem to change the link colors to black from blue and purple when clicked on. I just want all of the text to be black.

3- Is there a way to change the default register link to my forums register page? (I integrated word press into phpbbb using wp-united).

4- The page is kind of messed up in IE or google, it only seems to work somewhat okay in firefox.

If anyone wants to take a look at my Style CSS file that would help out a lot. Thanks.