Do not use <h2> and <h3> for visual styling. Those are sectioning elements, they are supposed to be used for titles of some kind of "section". If you want something centered, in bold and larger font, just say so with CSS:
Code:
<div class="centered_bold_and_larger">whatever</div>
div.centered_bold_and_larger {
text-align: center;
font-weight: bold;
font-size: 120%;
}