Here's what works for me. This assumes you've setup pop3 on your gmail account.

Account name: gmail
Account type: POP3
Name: your name i.e. Joe
User name: your gmail username i.e. banditrider
Password: your gmail password
E-mail address: your full email address i.e. banditrider@gmail.com
Incoming server(POP3): pop.gmail.com
Outgoing server(SMTP): smtp.gmail.com
Use connection specific SMTP servers: Un-checked

Advanced
Retrieval tab
Retrieve: Headers only
Leave email on server: Checked
Email size limit (kb): 1000
Password authentication: Normal
Security: SSL (POP3S)
Incoming e-mail port: 995 (you need to scroll down to see this)

Sending tab
SMTP authentication: Login
Username: full email address i.e. banditrider@gmail.com
Password: gmail password
Security: Normal (TLS)
Outgoing e-mail port: 587

Compositing tab
Default e-mail format: Formatted text (HTML)
Send email: Immediately
Include original in reply: Checked
Request read report: Un-checked

Security tab
Only the last two items are checked

Again, If you haven't set your account to pop3 at gmail.com, you won't be able to read mail.