Microsoft recently updated their web interface to the MS News newsgroups, adding new features, including the ability to mark posts that answered the question and marking posts as Helpful. If you're looking for help with a problem, it's easy to find answered questions and if you want to try your hand at answering some, it's easy to find unanswered questions.
You should also use this interface if you want to request a new feature or different behavior in an existing feature, choosing Suggestion as the message type. Posts marked as suggestions are pulled into a database for review. (mswish@microsoft.com can be used for these suggestions too.)
If you use Office 2003, you can access any of the Office newsgroups using the Communities link in the Help Task pane. It is linked with the appropriate newsgroups for the application (you can select newsgroups for other application using the menus).
From the Office website look for Office Communities near the bottom of the links on the left.
While using Outlook Express (or any other newsreader) is easier than the web interface, if you need help and can't use Outlook Express, any of the newsgroups carried on msnews.microsoft.com are available using the web interface at http://www.microsoft.com/communities/default.mspx.