Here's a follow up comment:
In another Android Forum I've been having a discussion with a few G1 phone users who have commented on the inconsistency of getting email notifications for the POP/IMAP email application. Most don't get any email notifications for defined POP accounts, but they do get notifications for IMAP accounts (under certain conditions).
For the IMAP accounts, they get notifications usually when the Phone is unlocked but not when it's locked. This seems like a real limiting factor with regards to usability.
Question: Does anyone know if there's a background service that is checking for new emails for the POP/IMAP accounts? There must be something, otherwise you probably need to have the email app up and running for it to do the checking (again, that would be a limiting factor).
Let' say that I did create a service that ran in the background and checked for new POP emails at a defined interval... would this service be running if the phone is locked? Also, could this service send out email notification alerts (icon displayed in the title bar and pull down shade) if the phone is locked?