After mere hours of App Catalog-stravaganza, the paid apps have been removed for the time being by Palm due to a major flaw in purchase verification. From what we've gathered from the seedy underbelly of the internet, an exploit involving building your own dummy application with the same name as a paid application allowed folks to download a free "update" to these falsified shells and score for-purchase apps galore without dropping a cent. Whether or not this was the only exploit afoot we're not sure, but it sounds like plenty of folks found ways to nab apps for free because Palm has clamped down hard on distribution for the time being. Optimistically, the company claims it should have the Catalog back up by tomorrow morning, but if the failure is really as severe as it sounds, we won't be holding our breath.
Update: And... they're back.
[Thanks to everyone who sent this in; picture courtesy of glamajamma]