It seems that OCSS has redesigned the skins pages to the bad-ass looking "Apache/1.3.9 Server at skins.counter-strike.net Port 80" style. Here's cliffe's short rant:
OCSS is undergoing changes. You can still download skins by going to http://skins.counter-strike.net/skins/ and browsing through the folders. The site will be under new management and up and running very soon.