Valve's Steam website has been updated with the latest news on this content delivery / authentication system. As you might've noticed, things didn't go exactly smooth during the weekend, as Valve seriously underestimated bandwidth needs. More servers are being added now. In addition to that, more Steam installers with cache files will be released for Day of Defeat, Team Fortress Classic, etc just like they did for Counter-Strike 1.6.
We know that the conversion process has been anything but smooth for many of our users. We're going to get this fixed. We've done our best to support the Half-Life community over the past 5 years, and we're still committed to doing whatever it takes to make the community happy. We've listened to the response, and we'll be repairing the problems with Steam until it performs the way we all want it to.