On the News Server Properties palette General tab you can change the name that appears on your posts, your e-mail address, and even change the news server name that will be displayed in your folder listing
Select the Advanced tab and check the plain text sending format. You can also change the port if the News Server requires a different one from the default.
Click the Maintenance tab and change the number of days before deleting to 30.
Set your Outlook Express News Reader to post in plain text and un-check the option to respond in the same format as the original post. This is the proper way to post in a public newsgroup. Many people use dedicated news readers that cannot display html posts and will not be able to help you if you post in HTML. If you MUST make a post in HTML you can select the Format > Rich Text option from the individual message you are writing.