Gmail on iPhone "username or password is incorrect"

"The user name or password for imap.gmail.com is incorrect"

To fix, go here and enable access:
http://www.google.com/accounts/DisplayUnlockCaptcha

But what you really want to do is create a one-time application-specific password:

• Go to Google account settings: https://www.google.com/settings/account
• Click "security"
• Click "Manage your application specific passwords"
• Create a new password and use that on your device

(source)

How to download a gmail attachment on mobile

How to download a gmail attachment on your mobile:

• Go to the gmail website on your mobile, the mobile version will load
• Click the 'Basic HTML' link at the bottom
• A download link will now be visible in your emails

Turn off gmail notification sound in Android

gmail app version 2.3.5.2:

• go to inbox
• press menu | more | settings
• select your account
• scroll down to the bottom
• select 'Labels to notify'
• here you can change the notification sound or disable it, set vibration and other settings

gmail without ssl/https

http://mail.google.com/mail?ui=html

Sending an email to yourself

You can't send an email from your blackberry phone, through a gmail account, and expect to see it arrive.
It just doesn't work. For reasons explained here:
http://www.blackberry.com/btsc/search.do?cmd=displayKC&docType=kc&externalId=KB18070
http://www.google.com/support/forum/p/Google+Mobile/thread?tid=196b521f8b4b7a76&hl=en

Make IMAP Gmail work on blackberry

If you enter your Google email address when prompted, there is no way to configure advanced settings to make IMAP accounts work. In fact, I called Orange and was told that their Blackberries do not support IMAP with Gmail, and it does not work.

But they are wrong. It does work - you need to enter an email address that is not one of the major commercial providers, but does host email accounts. I used a fake email alias @ a domain I know has a working mail record: siteaboutnothing.com

Then, as you follow the prompts, choose "Advanced settings" or similar, and you are able to set the server to imap.gmail.com and change the email address back to your gmail account.

I now have it set up so messages marked as read on my phone are sync'ed with my main gmail account and I don't have to manage two accounts at once.