The original idea’s from Tamar from her post to Google Support. You will need Greasemonkey Firefox plugin to use this. This works as a Google Chrome extension too.

Install the GMail Address Swapper GreaseMonkey Script.

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The script would swap the email addresses values between ‘TO” and the “CC” in your GMail compose page. This will work for any compose page (New email or replying to existing conversation).

A new icon (see screen shot below – the new image below the “TO” text) will be auto-inserted when you install the GMail Address Swapper GreaseMonkey Script.

Before

image

After

image

That’s it, The source code is available in the script itself and the SVN Repository is maintained on Google Code. If you need any modification to this, let me know on Twitter @Swaroop.

Update 1

I have just tested that this works on Google Chrome too (Without GreaseMonkey) – Just install the script from UserScripts.org. Let me know if you face any problems in Firefox or Chrome (Doesn’t need GreaseMonkey or GreaseMetal)

Update 2 (Oct 24, 2010)
Chrome 7.0 stable broke this extension. I found a typo in my code which was causing all the icons to appear. I have now fixed it and released the next update for GMail Address Swapper. Let me know if you’re still facing any problems.