How can I configure my Windows Phone to access a POP3 email account? My QQ email support POP3 service.

You can configure your Windows Phone to access your QQ email account using these steps:

1. Review your QQ email account help document and get the POP3 server information:

POP3 server name: pop.qq.com (port 110)
SMTP server name: smtp.qq.com (port 25)

2. Go to "Settings > email+account".

3. Tap on "add an account", and select "advanced setup". You see more instructions on how to finish up the advanced setup:

Advanced Setup
   Choose the kind of account you want to set up. 
   If you are not sure, check with your service
   provider.
   
Exchange ActiveAync
   Includes Exchange and other accounts that use
   ActiveSync
   
Internet email
   POP and IMAP accounts that let you view your
   email in a web browser

4. Tap on "Internet email", and enter the following settings:

Incoming email server: pop.qq.com
Account type: POP3
User name: 123456789
Outgoing (SMTP) email server: smtp.qq.com
[x] Outgoing server requires authentication
[x] Use the same user name and password for
    for sending email

5. Tap "Sign in".

6. Wait for Windows Phone to finish setting the email synchronization.

Now you can see QQ email in the application list and ready to use.