Sharepoint Result XML is not well formed

I am posting a request to the Sharepoint server using the GetListItems method,
providing the list name.  The returned XML is not well formed.  

 There is a portion of the XML which looks like:

<rs:data ItemCount="100"
ListItemCollectionPositionNext="Paged=TRUE&p_ID="100">

The &p_ID or somewhere should contain a semicolon.

In addition, it appears that the XML also includes some "html"
directives which are imbedded within the data.  For example I have something
that looks like 

<z:row ows_Description='<font size=1>the cat <br> is
black</font>' />

Every XML parser I run this data through complains that this is incorrect.  

I have to admit I am not running a Microsoft client for the access to the
Sharepoint site, but I WAS under the impression that these Web Services
functions were meant to be open. I can probably find workarounds for some of
these things, but wanted to post the question to find out if there is a way to
suppress the stuff that is invalid.

 Thanks.