MSXML4 : how to select a element with namespace prefix

Consider this sample...

<?xml version="1.0"?>
<alk:root xmlns:alk="http://foo" xmlns:xyz="http://goo">
	<xyz:bar>somevalue</xyz:bar>
</alk:root>

Using MSXML4 how to select the element "xyz:bar"

Without namespaces, i could do it simply via the "selectSingleNode" method.
How to do it when namespaces are involved?

thanks,
Laxmikanth