in C# fastest way to convert a string into a MemoryStream

I'm using an XPathNodeIterator to select an element in an XML document that
contains text I am going to put in a label on an aspx page.
I want to be able to include HTML tags in the text read from the XML
document, but the XPathNodeIterator.Current.Value property seems to ignore

I'm new to XML, so please bear with me.
I'm using XPathNavigator and XPathNodeIterator to return a set of xml nodes
from a document that looks like this:
<root>

I would like to be able to import the following xml document on a daily
basis to get the current exchange rates and then create the same output file
so
I can use Biztalk 2002 to import that file, but I am not sure how to do it?

I have a DataTable where one of the columns contains XML, when I add it
to a DataSet and call WriteXML it automaticaly encodes the XML (e.g. <
becomes &lt;) is there an easy way to prevent this encoding from
happening?

how to create a gif or png dynamicaly in .aspx and return in response?

how come when i do oGraphics.FillEllipse it draws blury? is there anyway to
adjust this default compression to not be blury when drawing a simple
ellipse?

When I try and load an xmldocument with its schema into an dataset. It
always returns 0 tables.
ds.ReadXml(Server.MapPath("\" & "data\ohsReport.xml",
XmlReadMode.ReadSchema)

I am building a personal web site in VS2005 as a kind of learing
project for myself, so forgive me if this is a novice question.
I am planning to use an XML file called SiteSettings.xml to hold
site-wide info such as copyright info, site title (e.g. my homepage)

I have created a vertical menu in asp.net using xml and xslt. Now i
want the link from the menu to show in the iframe witch is a small part
of the complete website. I don't want the main page to refresh so
setting an iframe would be very cool.

I've got the following validation problem. There are 2 schemas and a
document:
-----------------------------------------------------------------
bar.xsd

I would like to write a C# program to read in a .xsd document, traverse it's
nodes, and write out a new, modified xsd. I can't seem to find any .Net
methods that allow me to traverse the XSD. Suggestions?