We do not provide a way to delete a TouringPlans.com account.
If you no longer wish to use your TouringPlans.com account, you can simply stop using it. Our subscriptions do not automatically renew, so existence of the account does you no harm. Plus, if you decide to subscribe again the next time you plan a trip, you can use the same account.
Finally, if you want to change information in your account (username, email address, password, etc.), you are welcome to do that. Simply login to your account and click the "Edit" link next to Your Profile on your dashboard.