Office 365, Gmail, Email, Where do I log in?
Note that you must have an account on that email system to be able to log into the web interface.
Exchange Email (staff, faculty, graduate students, retirees)
Exchange Online (Office 365) (staff, faculty, graduate students, retirees)
MS article on using Outlook on the Web:
Google Apps @ Illinois
If you have any questions or concerns about your campus email, contact the Technology Services Help Desk for assistance.