A condensation of your description code in view source:
HTML Code:
<!--bof Product description -->
<div id="productDescription" class="docProduct biggerText">*</span><span class="style3">*</span><span class="style4">*<span class="style5">FREE P&P TO UK MAINLAND ONLY</span>*</span><span class="style3">*</span><span class="style2">*</span></p>
<p class="style7">Printed onto a Silk 170 gsm Photographic Poster Paper at A1 size (594 x 841 mm - 23.4 x 33.1 inch) Landscape.</p>
<p class="style8"> </p>
<p class="style11">.:: Disclaimer ::.</p>
<p class="style12">Whilst care is taken to ensure that the End design Media Ltd t/a Canvas Style Art website is as ... equally disclaimed by Canvas Style Art itself.</p>
<p class="style9">.:: Copyright ::.</p>
<p class="style12">2008 Canvas Style Art. All Rights Reserved. All text, images, graphics, and other materials... written permission of Canvas Style Art. </p>
<p class="style10">© Copyright 2008 - Canvas Style Art.</div>
<!--eof Product description -->
If you want to copy this block essentially as is to all products, you can leave the "style#" classes alone (though best practice is to give classes meaningful names), and just do the work in your stylesheet (/includes/templates/your_template/css/stylesheet.css).
It is possible that generic names like style9 could be used elsewhere in your site, so you can specify that your declarations only apply to ones in the product description:
Code:
#productDescription .style9, #productDescription .style10, #productDescription .style11 {font-size: 0.9em;}
#productDescription .style12 {font-size: 0.8em;}