How people get a page on Google News?

Being at least a somewhat credible outlet of news. Not simply issuing some press releases or anything; being somewhere people turn for news outside of Google.

I think that google has a spider that goes so some well known news sites and get the news from them.

PRweb can help a lot in getting there.

I also have a question, how Google differentiate what is news and what is blogging?

See what news outlets Google indexes and then determine which ones would accept submissions from you. If you are a good writer or have valuable content to offer, some might publish your stuff. And just like that - voila - you'll be in Google News.