OK. Open your gmail account, click on the Settings button at the top right (looks like a wheel). Then click on "Accounts and Import" tab (3rd from left), then locate "Change Account settings" and under that the blue hyperlink "Other google account settings". A new page will open, click on the "Edit" blue hyperlink next to "My products". Then click "remove gmail permanently".
or just this: http://www.google.com/support/accoun...y?answer=61177