To configure Outlook 2007 for your Gmail address:
Enable POP in your email account. Don't forget to click Save Changes when you're done.
Open Outlook
Click the Tools menu, and select Account Settings...
On the E-mail tab, click New...
If you are prompted to Choose E-mail Service, select Microsoft Exchange, POP3, IMAP, or HTTP, and click Next.
Fill in all necessary fields to include the following 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 (username@gmail.com). Google Apps users, enter your full address in the format username@your_domain.com.
Password: Enter your email password.
Manually configure server settings or additional server types: Leave this option unchecked if you want to automatically configure Outlook 2007. If you want to manually configure Outlook 2007, check this box now. Google Apps users should configure manually as follows.
If you are configuring Outlook 2007 manually, select Internet E-mail and click Next.
Server Information
Account Type: POP3
Incoming mail server: pop.gmail.com (Google Apps users, enter the server names provided, don't add your domain name in these steps)
Outgoing mail server (SMTP): smtp.gmail.com
Logon Information
User Name: Enter your Gmail username (including @gmail.com). Google Apps users, enter your full address in the format username@your_domain.com
Password: Enter your email password.
Require logon using Secure Password Authentication (SPA): Leave this option unchecked.
Click the More Settings... button, and select the Outgoing Server tab.
Click the Advanced tab, and check the box next to This server requires an encrypted connection (SSL) under Incoming Server (POP3).
Click Test Account Settings... After receiving 'Congratulations! All tests completed successfully', click Close.
Congratulations! You're done configuring your client to send and retrieve Gmail messages.