2.  I want to do a number like <xsl:number level="any" count="productId"/>.
However, I only want to get the xsl:number for productId that has publisher
of "NETg" or "Wave".

3.  Same question is for count(//productId).  How can I do a count of
productId that has publisher of "NETg" or "Wave"?

Try
 productId[publisher='NETg' or publisher='Wave']
in either case.

You should make up your mind whether it is productID or productId,
there is a difference. And, well, consider working through a good
XSLT book.