If you're using Microsoft's Internet Mail and News [program] (which is built into some versions of the Explorer 3.x), you'll notice that it does not let you change the directory where your data files (mail and news) are stored. By default, it will store your mail and news in "C:\Microsoft Internet\Internet Mail and News\<current user name>." Here's how to change this location:
Close Microsoft Internet Mail and News
Run Registry Editor ("Start Menu | Run | Type RegEdit and press ENTER")
Change to the following registry key:
"HKEY_CURRENT_USER\Software\Microsoft\Internet Mail and News"
Double click on "Store Root"
Type in the new directory where you want to save your Internet Mail and News files in
Click OK and exit the Registry Editor
You may or may not want to move your old data files from the original mail/news directory to your new directory
Restart Microsoft Internet Mail and News