try this url out
it is the same for "ME" and "98" and it is easier than it looks
You can easily enable Internet Connection sharing, using the Add/remove Programs applet in control panel(internet sharing), and using the Network Connection Wizard and Dialup Properties (probably already done that bit)
http://www.microsoft.com/HOMENET/ics.htm
Mailbox is a bit tricky (maybe not in ME) but generaly you would need to configure an exchange server.
One alternative to just use a shared folder or web share a virtual directory.
Hope this helps