Google just began to roll out IMAP support for Gmail. One of the most requested Gmail features was the addition of IMAP support. POP is nice, but IMAP is a much better option. Among the advantages, you’re always connected to the server, more clients can connect to the same account, you can obtain the text from a message without the attachments and the state information is synchronized (you can add labels from the client, read or delete a message and Gmail will synchronize).
Gmail added IMAP support, but you’ll have to enable it by going to Settings > Forwarding and POP/IMAP. Because the new feature is slowly rolled-out, you may not see it, but rest assured it will be available in the next days. Gmail’s help provides more information about configuring your client, whether it’s Microsoft Outlook, Thunderbird, Blackberry, iPhone, Windows Mobile or Symbian device.
If you’re settings page looks like this, you have IMAP available now:
If you’re setting page still looks like this one, then you’ll have to wait a day or two:
I just set this up for one of my Gmail accounts and it works flawlessly. Since I’m all about the iPhone now, here are directions on how to setup the iPhone for use with Gmail. https://mail.google.com/support/bin/answer.py?answer=77702