Just got an email from sitepass:

...Everything from Visa regulations on processing transactions to the latest anticipated 2257 changes have created an environment that we must adapt to in order to continue to prosper and bring webmasters a wide range of programs. That being said, it is to my displeasure that I must inform all of our webmasters that as of September 1st, 2004, SitePass will be closing down for good.
I never used them but I wonder if its an indication of things to come!

cheers,
Luke