Yes, you can using the DSi's internet browser.
it means you can log on to the account, answer mails sent and send out emails, it means you can do anything
If you are referring to Microsoft Outlook Express, then you need to set up the account info on that computer. To do this do it the same way you did on your personal computer. If you are referring to...
You need an e-mail account, an internet connection and a computer. In the related links box below I posted the wikipedia article on e-mail.
don't.