According to Mary Jo Foley yesterday, Microsoft is providing Silverlight 1.0 as an optional Windows update starting today. It isn't one of the required updates that automatically gets installed for most users, so they'll have to manually select it but it will show up on the list. Also as Mary Jo notes, the updates will now be part of the batch that IT staff have discretion to install in their environments and push out to business users. That may mean a bump in Silverlight 1.0 installs inside the firewall.
A lot of users have had issues with installing both the 1.1 alpha and the 1.0 version of Silverlight. Because I had the alpha installed I kept getting errors telling me that the Silverlight plugin wasn't installed. I really hope for everyone's sake that the upgrade process between 1.0 and 2.0 is smoother than it was for the 1.1 alpha. All the cool stuff is in 2.0 so hopefully the experience is better than it has been.
It's going to be a pretty interesting ramp up to MIX. There are a lot of content deals around Silverlight stuff and now 1.0 will go out to a chunk of users. Now we just have to wait and see what's in store for 2.0.
More info at RIApedia.