Scott mentions that Don told him that Indigo will be available for non-Longhorn versions of Windows sometime after the release of Whidbey.  Now, this is cool.  I haven't had a chance to play with Indigo yet, but I'm dying for the opportunity.  If/When I play with it I'm going to want to implement something and if/when I implement something I want it to be able to run on as many machines as possible.  I was quite concerned that only Longhorn would support all these wonderful new toys. (Which I understand is the point of Longhorn.  Show us something shiny in the hopes that we will want it.  Well we want it, and we want our old toys too, dang it!)