Import Old mail Using IMAP

IMAP, or Internet Message Access Protocol, lets you download messages from Gmail’s servers onto your computer so you can access your mail with a program like Microsoft Outlook Express or Apple Mail, even when you aren’t connected to the Internet.IMAP creates a constant connection between mail clients (desktop and/or mobile) and Gmail.

Setting up IMAP and Import Old Mail using IMAP

To enable IMAP in Gmail:

1. Sign in to Gmail.
2. Click Settings at the top of any Gmail page.
3. Click Forwarding and POP/IMAP.
4. Select Enable IMAP.
5. Select Save Changes.
   

Setting up IMAP on the email client. Refer here for more setup for other email client

1. Open Outlook.
2. Click the Tools menu, and select E-mail Accounts…
3. Click Add a new e-mail account, and click Next.
4. Choose IMAP as your server type by clicking the radio button, and click Next.
5. Fill in all necessary fields to include the following information:
   

   User Information
   Your Name: Enter your name as you would like it to appear in the From: field of outgoing messages.
   Email Address: Enter your full Gmail email address Server Information
   Incoming mail server (IMAP): imap.gmail.com
   Outgoing mail server (SMTP): smtp.gmail.com

   Login Information
   User Name: Enter your Gmail username
   Password: Enter your Gmail password
   

6. Click More Settings… and then click the Outgoing Server tab.
7. Check the box next to My outgoing server (SMTP) requires authentication and select Use same settings as my incoming mail server.
   
8. Click the Advanced tab, and check the box next to This server requires an encrypted connection (SSL) under Incoming Server (IMAP).
   
9. Check the box next to This server requires an encrypted connection (SSL) under Outgoing Server (SMTP), and enter 465 in the Outgoing server (SMTP) box.
10. Click OK.
11. Give a name to the mail account to differentiate with other email account.
    
12. Click Test Account Settings… After receiving Congratulations! All tests completed successfully, click Close.
13. Click Next, and then click Finish.

Transfering file using IMAP

1. Launch the Microsoft Outlook 2003, you will able to see a folder name same as the Mail Account name you have specific just now.
   
2. To transfer old email in your Microsoft Outlook 2003 to Gmail Apps, just drag and drop the email from your personal folder to the folders under IMAP account.