CIW, Certified Internet Webmaster, is offered by ProsoftTraining, Inc. The basic certification offered is known as CIW Associate. This can be obtained on passing CIW Foundations (exam 1D0-410) exam. The next level of certification is CIW Professional. For obtaining CIW Professional qualification, you need to pass CIW Foundations exam and any one of several optional subjects offered by Prosoft Training. These optional subjects include, but not limited to: 

 CIW Site Designer (exam 1D0-420)
 CIW E-Commerce Designer (exam 1D0-425) 
 CIW Server Administrator (exam 1D0-450) 
 CIW Internetworking Professional (exam 1D0-460)
 CIW Security Professional (exam 1D0-470) 

CIW Web Developer (exam 1D0-532), and  CIW Security Analyst   
These certifications require the following:
Passing score on CIW Security Professional (exam 1D0-470)
Submission of proof of your qualifying certification (see prerequisites) via fax to the ProsoftTraining Certification Department.

You can view further details at the Prosoft Training's CIW website, http://www.ciwcertified.com/
You can download some CIW practice tests here.