How can i match
<ejbbnd:EJBJarBinding >
element ?
and where do I have to declare the namespace in the stylesheet ?

Declare whereever it would be of some use. In many cases declaring
it on the stylesheet document element is the most convenient way:

<xsl:stylesheet version="1.0" xmlns:xsl="..."
  xmlns:ejbbnd="...">

  <xsl:template match="ejbbnd:EJBJarBinding">
    ...