Ok, so on your phone press the menu key, the first hard key on the left if you are holding the phone as if you are talking on it and the last key on the bottom if you are holding the phone in landscape mode.
1) touch "Settings"
2) scroll to "Accounts" and touch it
3) touch "Add account"
4) find your account type and touch it (I have 3 e-mail accounts that I use on my phone: G-mail, Yahoo, & Corporate Sync (my work e-mails))
5) then you will just have to enter & set-up each different e-mail account using the account settings. For most of them you just enter your e-mail address & password.
There you go!!!
Post here if you have any problems.