You cannot delete your account, yet from the FAQ we learned the following:
To access, change or delete the personal information about your child on the Sites, log into the www.pokemon.com site and follow the instructions to unregister or contact us at The Pokemon Company International, Attention: Privacy Policy Administrator, 333 108th Avenue, NE, Suite 1900, Bellevue, WA 98004, Fax: +1 (425) 274-1041.
We’d suggest you check http://support.pokemon.com/ to file a ticket.
URLS:
http://pokemon.com
Please note that AccountKiller.com is not associated with the business listed on this page. AccountKiller provides easy-to-understand instructions and guides on how to cancel charges and relationships from the list of businesses on our site, we have no affiliation with these businesses.