If you're not using a major online service provider, you can still set up and use any standards-based email, calendar, and/or contacts service you like, including your own!
- Launch the Settings app from your Home screen.
- Tap Mail, Contacts, or Calendar.
- Tap Accounts.
- Tap Add Account.
- Tap Other.
- Select the account you wish to configure.
- Enter in your service information. If you don't know it off-hand, you'll need to get it from a system administrator or whomever runs your IMAP/PPO, CalDAV, and/or CardDAV account.
- Tap the Next button in the upper right hand corner, and your device will verify the account.
- If everything looks right, tap on Done. Your account will now start syncing with your iPhone, iPad, or iPod touch.