> I have a client passing me a feed with a top-level element
> that looks like this:
>
> <ArrayOfProductType
> xmlns:xsd="http://www.w3.org/2001/XMLSchema"
> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
> xmlns="http://catalog.9squared.com">
>
> Now, am I mistaken in thinking that namespace declarations
> are inappropriate in an XML feed? And if I am mistaken, how
> do I work with that? I even duplicated these namespace
> declarations in my xsl and then pointed them to resolve to
> the xsl namespace, but I am still getting nothing to output.

All elements in the above feed are in the 'http://catalog.9squared.com'
namespace, so in order to match them you will have to declare that
namespace in your stylesheet, give it a prefix and then match elements
with that prefix:

<xsl:stylesheet xmlns:foo="http://catalog.9squared.com" ......

And then:

<xsl:template match="foo:whatever">.....


Read here for more 'Matching nodes in the default namespace' info:

http://www.dpawson.co.uk/xsl/sect2/N5536.html#d6408e1012

cheers
andrew