Retrieving and filtering News Items from the webservice

Hello,

I am trying to utilize the built in web services to work with the news items on the client side.  I am struggling to figure out how to filter by categories.  Can anybody provide some examples on how I can get this to work? 

I can get the title filtering to work but I am not sure how to filter classifications.

~/sitefinity/services/content/newsitemservice.svc/?=title="TitleText"

Scott