Hi!
To manage newsgroups in Outlook 2003 without Outlook Express you should
use 3rd party add-in. Try our MAPILab NNTP for Outlook, 30 days trial:
http://www.mapilab.com/outlook/nntp/
MAPILab NNTP allows you to read and post messages to newsgroups from
Microsoft Outlook 2000, 2002/XP and 2003. This product is a
full-function MAPI transport. This means that a news server account
works in the same way as an account for Microsoft Exchange Server or a
POP3/SMTP account, support remote mail headers and it is managed through
common Send/Receive menu.
MAPILab NNTP for Outlook supports all messages formats (plain text, RTF,
HTML) and encodings which are supported by Microsoft Outlook. It is
fully compatible with (but doesn't require!) Microsoft Exchange Server
and can be used to share newsgroups for coworkers through public
folders.