Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Update...

After days of following the tutorials on Apple and at Google of trying to figure out why I have not been able to retrieve my email properly from Gmail via POP on both my Mac and iPhone (since updating to iPhone 1.1.3), I have found that the "Use Recent Mode" tab is not an option in the POP settings. I am referencing the following articles:

http://docs.info.apple.com/article.html?artnum=305937
http://mail.google.com/support/bin/answer.py?answer=72454
http://mail.google.com/support/bin/answer.py?answer=47948

Each mentions using Recent Mode for retrieving mail on multiple POP clients, as I do. At the moment, I am manually entering these settings on my Mac's Mail.app and my iPhone's Mail.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.