Head to your Labs settings and enable the “Refresh POP accounts” lab, then hit “Save changes” at the bottom or top of the page. From then on, you’ll see a “Refresh” link to the right of your inbox buttons. Hit it and Gmail will poll any email accounts you've set it up to fetch from. Want to get started importing your other mail accounts into Gmail? Check out Gina’s guide.
This is excellent news for those who read their POP3 mail from Gmail. No more navigating into the settings page to refresh the mailbox.