Outlook Express is a email client. You use it to retrieve email from an existing email account, usually one that is given to you by your internet provider. If you are looking for an free email client to use other then Outlook Express there are many choices although the most popular alternative is probably
Thunderbird.
If you are looking for an email service provider there are many web based ones you can choose from and requite less setup then Outlook Express or Thunderbird. Again there are many free ones to choose from but
Hotmail,
Yahoo! Mail, and
Gmail are probably the three biggest ones. Personally I would recommend Gmail because of the excessive amount of storage space they give you, clean easy to use interface, and the ads on their site are not as intrusive as the ones on Hotmail or Yahoo!.
I'll be happy to help you further if you need it.