Gmail adds IMAP supportOctober 24, 2007
Gmail now supports IMAP, which makes it truly the ultimate free email solution [post]! This means you can now use Gmail seamlessly on your iPhone. I set it up in 60 seconds and it works perfectly. This means I no longer have to go through the web browser to check email, though Google greatly improved that interface recently. Plus, writing new messages just got much easier. Of course, you can also use a desktop mail client like Apple Mail as well.
While waiting for Gmail to add IMAP support, I experimented with using Yahoo mail just for use on the iPhone and was very disappointed. I would often not receive messages for more than 24 hours, then suddenly receive a batch all at once. Hopefully, Gmail will be much more reliable.
If you don't have the IMAP option [article] within your Gmail settings yet, try logging out and logging back in. That worked for me.