There is a couple places to look for that, its either in the css file, I believe its called style.css or whatever, or the header.php
<!-- ^^^^^^^^^^^^^^ header code ^^^^^^^^^^^^^^ -->
<div id="header">
<div id="pagenav">
<ul>
<li class="current_page_item"><a href="http://www.nick.eagleconnections.net">Home</a></li>
<li class="page_item page-item-2"><a href="http://www.nick.eagleconnections.net/about" title="About">About</a></li>
</ul>
</div>
<div id="searchform">
<form method="get" action="http://www.nick.eagleconnections.net/">
<fieldset>
<label>Blog Search</label>
<input value="" name="s" id="searchinput" type="text">
<input value="Search" id="searchbutton" type="submit">
</fieldset>
</form>
</div>
<div id="logo">
<h1><a href="http://www.nick.eagleconnections.net/" title="Nick’s Blog">Nick’s Blog</a></h1>
<div class="description">My ramblings about whatever comes my way. Websites, vBulletin, Forum Management, Photography, Animals and more.</div>
</div>
<!-- ^^^^^^^^^^^^^^ please modify ^^^^^^^^^^^^^^ -->
<!--<div id="about">
<p>My ramblings about whatever comes my way. Websites, vBulletin, Forum Management, Photography and more.</p>
</div>-->
<!-- ^^^^^^^^^^^^^^ please modify ^^^^^^^^^^^^^^ -->
</div>
<div class="clear"></div>
<!-- ^^^^^^^^^^^^^^ header code ^^^^^^^^^^^^^^ -->
Yeah you need to look for the css definitions for logo. Thats the class that is defining that

I made it bold and red so you could see...I hope that helps