Upgrading from Volunteer to Supersponsor via Online form?

I read the FAQ:

Upgrading your membership is as easy and dropping a letter into the mail. Let us know what your current membership level is and the level to which you wish to upgrade. Enclose payment in the form of a check, a money order, or a legible photocopy of your credit card (along with its billing address). If upgrading to a sponsorship or a supersponsorship, make sure to tell us what your T-shirt size is!

Alright, I'm just thinking of an easier way here to register for SuperSponsor without having to mail anything. I went SuperSponsor last year, I loved it, and I want to do it again! The idea of mailing something is kind of... I dunno... strange to me because of how long it took to respond the last time I mailed something. I know that you're busy... believe me... I know busy (I work retail for a living.) If mailing in a payment (a money order will probably be what I am going to do) is the only way to upgrade to SuperSponsor from Volunteer, then I'll go ahead and do that. I just wonder why there wasn't a way to upgrade via the Internet.

Thanks if you can help.