Have you tried the automatic configuration tool for gmail configuration if not try from the link below :
http://mail.google.com/support/bin/answer.py?answer=13276
for manual configuration on outlook use following steps
To configure your client manually:
Enable POP in your Gmail account.
To enable POP in your Gmail account, please follow these steps:
Log in to your Gmail account.
Click 'Settings' at the top of any Gmail page.
Click 'Forwarding and POP' in the orange 'Mail Settings' box.
Select 'Enable POP for all mail' or 'Enable POP for mail that arrives from now on.'
Choose the action you'd like your Gmail messages to take after they are accessed with POP.
Configure your POP client* and click 'Save Changes.'
Open Outlook or Outlook Express.
Click the 'Tools' menu, and select 'Accounts...'
Click 'Add,' and then click 'Mail...'
Enter your name in the 'Display name:' field, and click 'Next.'
Enter your full Gmail email address (username@gmail.com) in the 'Email address:' field, and click 'Next.'
Enter 'pop.gmail.com' in the 'Incoming mail (POP3, IMAP or HTTP) server:' field. Enter 'smtp.gmail.com' in the 'Outgoing mail (SMTP) server:' field.
Click 'Next.'
Enter your Gmail username (including '@gmail.com') in the 'Account name:' field. Enter your Gmail password in the 'Password:' field, and click 'Next.'
Click 'Finish.'
Highlight 'pop.gmail.com' under 'Account,' and click 'Properties.'
Click the 'Advanced' tab.
Check the box next to 'This server requires a secure connection (SSL)' under 'Outgoing Mail (SMTP).'
Enter '465' in the 'Outgoing mail (SMTP):' field.
Check the box next to 'This server requires a secure connection (SSL)' under 'Incoming mail (POP3).' The port will change to 995.
*The order of 'Outgoing' and 'Incoming' mail server fields varies by version. Make sure you enter the correct information in each field.
Click the 'Servers' tab, and check the box next to 'My server requires authentication.'
hope this helps.