document(strHTML) ?

I have an XML RSS blog feed which includes in the description text node
a chunk of HTML.  I'd like to apply templates down into the contents of
that HTML string, so that I can render it as part of a new HTML page
based on the larger XML RSS item record.  As it is now, when I process
the description node, the HTML page displays the raw HTML string,
including the markup tags.  Ugly.  If I view the HTML source, the tags
have been rendered like:

<P>

I have a feeling there is a simple answer to this, haven't found one so
far, so thought I'd ask about it while I continue researching.  It seems
like a common need.  

Thanks in advance,

Jon Schwartz