Centering Social Bookmarks and Navbar Text??

Wrap ’em in a div or two and give it the property style="text-align:center;"

You have two options:

a)
You do it like this:
<div style="text-align:center;">Your content that is to be centered goes here</div>
In this case you need to do this once to your navigational links in the header and once around the bookmark icons. If you use a plug-in for the bookmarks, it depends on the plugin you use.

b)
Or you do it via your css. In that case, you begin like before, only this time it is:
<div class="pick_any_name_for_your_class">again, your content goes here</div>
and add this to your stylesheet (anywhere in your stylesheet, preferably at the bottom):
.name_of_your_class { text-align:center; }

The latter has the advantage that you can also use this for future changes, simply wrapping the <div class="name_of_your_class"></div> around anything that can be centered (works for me on text, pics, embeds, javascript, iframes), wether it is part of the design or a post (unless you write posts using the visual editor).

if you want the text to be aligned to the left or right (not center) and just want the column to be centered, then try the ‘float’ command instead of text-align.
You can use both text-align and float and have different values for them.