It would be one thing of the email was from the person, but it sounds as if your form is sending you an email with POST info. The only thing I could think to pull that data out of a gmail account would be by hand. If you loaded the imap info into an easy to use email software, you could get the job done in a fairly short amount of time. In the future I'd suggest something like what blacknight said, have the email and any other pertinent data get posted to a DB before or while getting sent to your email account, or just use an opt-in form from your email marketing provider (aweber/getresponse/etc)