You can configure Outlook to be your default newsgroup reader (Control
Panel - Internet Options - Programs), but the thing is, it's just going to
open the Outlook Newsreader in OE when you click on Views - Go To - News.
Still, you don't have to separately open OE to get to the newsgroups -
though clicking it will bring up the OE newsreader window, but the features
will be customized and targeted for newsgroups.